Astro Physics 130 EDT vs. Takahashi FS-128
Albert Canarelli
far, the wait has been only to get on the official Astro Physics waiting
list...where I will wait another 12 to 18 months or more before I will ever
see the scope. Moreover, it is not a given, at this time, that I will be on
the next Astro Physics production run. AP tells me that they may use a
lottery system to select new buyers! I confess that my resolve (very strong
about 6 months ago) is starting to falter. I've dreamed of owning a
wonderful instrument like this for years, but this waiting is a killer!
Recently, I have considered abandoning the idea of buying an AP in favor of
buying a more readily available scope such as a Takahashi. I know very
little about a Takahashi and hope that some of you may provide me with some
of your experience. My question is this: What would I be giving up (if
anything) if I purchased a Takahashi FS-128 rather than an Astro Physics 130
EDT? Any information that you may pass on will be appreciated and most
helpful...thank you for your time.
Al Canarelli
Shedir
>anything) if I purchased a Takahashi FS-128 rather than an Astro Physics 130
>EDT?
I've never looked through a Tak 128 but from what I understand from
talking with owners is that they are very good scopes indeed but most would
still rather own the AP 130. Another thing to remember is that the new AP 130
EDT coming out this spring is not the same scope Roland put out a few years
back. It's an f8.3 version and will use the EDF glass. Roland told me it's
bascially a 155 f7 EDF stopped down to 5 inches. According to Thomas Back it
will be the best corrected scope AP has ever produced. Something to consider
before making a hasty decision.
HC
about the APM APOs? I have heard many good things
about them.
Todd Gross
Herb York
C.G. Anderson
You are experiencing the same woes I dod when I ordered my AP mount
Wait, wait, wait, wait, wait..........wait! Does the fact that there is
a possible lottery tell you anything? I don't own an AP scope, but I do
have the AP900 GOTO. I waited nine long months for it, and I too had
second thoughts (almost canceled my order twice: once to buy a Deering
banjo, and the second time to get a Losmandy mount). The quality of the
AP mount is second to none. Looking back now if I hadn't waited, I'd be
regretful. Judging by what others have said, and the image they have
produced, the AP scopes are equally well made. Good things come to those
who wait. The stars will still be there in a year.
Chris
Albert Canarelli wrote:
>
> I have been waiting (money in hand) since last October to buy an AP 130. So
> far, the wait has been only to get on the official Astro Physics waiting
> list...where I will wait another 12 to 18 months or more before I will ever
> see the scope. Moreover, it is not a given, at this time, that I will be on
> the next Astro Physics production run. AP tells me that they may use a
> lottery system to select new buyers! I confess that my resolve (very strong
> about 6 months ago) is starting to falter. I've dreamed of owning a
> wonderful instrument like this for years, but this waiting is a killer!
>
> Recently, I have considered abandoning the idea of buying an AP in favor of
> buying a more readily available scope such as a Takahashi. I know very
> little about a Takahashi and hope that some of you may provide me with some
> of your experience. My question is this: What would I be giving up (if
> anything) if I purchased a Takahashi FS-128 rather than an Astro Physics 130
> EDT? Any information that you may pass on will be appreciated and most
> helpful...thank you for your time.
>
> Al Canarelli
--
Chris Anderson
Eddyville, KY
"The real problem is not whether machines think
but whether men do." -B. F. Skinner
Darklight Imagery web page:
http://www.darklightimagery.net
mailto:thx...@apex.net
TMBack
> I've never looked through a Tak 128 but from what I
>understand from talking with owners is that they are
>very good scopes indeed but most would still rather
>own the AP 130.
I have carefully compared the Tak FS-128 (and
owned a Tak FS-102), and I can assure you that the
Astro-Physics 130mm EDT has significantly better color
correction than the 5-inch Tak. There has been a lot of
talk lately on s.a.a., about "APO" doublets not showing
chromatic aberration, but it is quite easy to see with high
magnification and a bright star. The other point to consider
is that the large violet halos (even if they are not visible
in viewing a planet), wash the contrast down and act like a
yellow filter. If anyone doubts this, just setup a Meade ED
and a Newtonian side-by-side, on Jupiter. You will notice
that Jupiter is much whiter in the Newtonian, and has a
yellowish cast in the ED lens.
You might ask, so what? Well, besides the above
mention loss of contrast, it also degrades planetary
color purity, especially blue features like the festoons.
> Another thing to remember is that the new AP 130EDT
>coming out this spring is not the same scope Roland put
>out a few years back. It's an f8.3 version and will use the
>EDF glass. Roland told me it's bascially a 155 f7 EDF
>stopped down to 5 inches. According to Thomas Back it
>will be the best corrected scope AP has ever produced.
This is true, the new AP 130EDT is really the 155EDF
stopped down to 5.1-inches, and the level of color, spherical
and spherochromatism is the best of all the production apo-
chromats that Roland has ever made. One correction, however.
Roland has made some custom long focus apochromats, and
a few wide air-spaced lenses that have an even higher degree
of optical correction.
Thomas Back
JAYSEEJAY
up the phone with the AP and speak with the designer if you have a problem.
Jay
TMBack
>This is complete and utter BS. I have compared the
>two with _more_than_one_sample_ from each brand.
>If you pick any two at random about half the time the
>Tak will show _very_slightly_ more colour, the other
>half of the time the AP will. Essentially the quality is
>identical.
I'm talking about violet color correction. It is not
"utter BS." You obviously have little or no understanding
of the color correction in AP FPL-53 triplets vs. the Tak
doublets. Spot diameters at 4358A are about 50 microns
in the Tak, the AP are about 5x better in the new 5.1"
f/8.3 EDT design.
>Visually the Tak has a slight edge, due to the higher
>light transmission. But it is avery slight edge, and
>personally I would not use this as a deciding factor.
Now this _is_ utter BS. The transmission of an oil triplet
with the high transmission glasses that Roland uses,
and high quality multicoating puts the transmission above
the 97.5% to 98% mark. A fully multicoated Fluorite
doublet has transmission at 97+% in the visible. The
AP has the higher light transmission, but the difference
is not detectable to the eye (less than 1%).
>Photographically the performance is also almost
>identical, with again a slight nod going to the Tak
>for better transmission/colour correction (the APs
>seem to have less blue correction in photographs.)
This statement is incredible It is at once contradictory,
and false. Just look at the last 5 years of S&T published
deep-sky photographs, and tell me what telescope has
the better photographic performance?
>AP has a good product.
AP has a great product.
>You don't need to feel so insecure about your purchase
>that you have to lie about competitor's products.
I have no such insecurity, as I have owned and used
both companies products. The comment about lying, is
not something I take lightly, Mr. Horr.
Thomas Back
CMUDUDE101
Ive heard of Thomas Back, and know of his optical knowledge.... Ive NEVER heard
of you Gene Horr, but the past few weeks iv read your posts all you seem to do
is bash astro physics. Whats with that?
As for the comparision, Ive heard from countless others they would rather have
the AP over the tak <this also includes 128 owners. myself included!>
Sean
mark dambrosio
So i guess it depends on which Losmandy mount your talking about. Scott
now claims about a 7 moth wait for the HGM, but sometimes his figures
can be a little on the optimistic side.
I have now recently decided to be put on a waitng list for an AP1200GTO,
and will sell the HGM-200. If the AP is ready in 9 months, i will be
quite happy. Mark
RAnder3127
>I have been waiting (money in hand) since last October to buy an AP 130. So
>far, the wait has been only to get on the official Astro Physics waiting
>list...where I will wait another 12 to 18 months or more before I will ever
>see the scope
Consider the APM apos as well. $2000 for the 4".
-Rich
"Of course NATO should stop the Serbs, but if America's
experience with the Afghans is any guide, NATO will get
ZERO thanks from the Kosovars when this is over."
Rich N.
send an email (which I did earlier) but I too have
done side by side comparisons with more than
one Tak FS-128 and my 130EDT and I have looked
through other 130EDTs.
The FS-128 is a fine refractor. It does give bright, high
contrast images, I wouldn't mind having one, however,
I don't think it is better than the AP130EDT. I wouldn't
trade my 130EDT for the FS-128.
Rich N.
ddd wrote in message <370c0fa7....@news.texas.net>...
>On 5 Apr 1999 19:14:29 GMT, tmb...@aol.com (TMBack) wrote:
>This is complete and utter BS. I have compared the
>two with _more_than_one_sample_ from each brand.
>If you pick any two at random about half the time the
>Tak will show _very_slightly_ more colour, the other
>half of the time the AP will. Essentially the quality is
>identical.
>
>Visually the Tak has a slight edge, due to the higher
>light transmission. But it is avery slight edge, and
>personally I would not use this as a deciding factor.
>
>Photographically the performance is also almost
>identical, with again a slight nod going to the Tak
>for better transmission/colour correction (the APs
>seem to have less blue correction in photographs.)
>But it is a very slight difference. And I am picky
>about my photographs and again I would not make
>this a deciding factor.
>
>The Taks are more aimed at medium and 4x5
>photography, with flat unvignetted image circles
>out to 90mm in size and field flatteners and focal
>reducers up to 4" in size. But if 35mm is your goal
>then you are purchasing performance that you will
>never use (the _smallest_ Tak focal reducer is
>68mm).
>
>AP has a good product. You don't need to feel so insecure about
>your purchase that you have to lie about competitor's products.
>
>Gene Horr
>trarubee ng fjoryy qbg arg
>
>ROT13 to reply
>
>
>
>
Rich N.
Wow, you have really gone over the edge!
Are you sure you were looking through an AP 130EDT or
one of the older non-ED 127 APs?
I have no connection to any telescope company. I'm just a
refractor nut. I have 3 AP OTAs and 3 Tak OTAs. Several
people in our observing group have Taks and several have
APs. I get out and observe with these scopes as often as
I can. I am not getting my opinions from a book. I like both
Takahashi and Astro-Physics telescopes.
Again, I have done side by sides with two FS-128s. My 130EDT
I believe uses the FPL-52 ED glass. It is very well color corrected.
It is so good I can't see any false color in the in focus image. The
new 130EDTs are using FPL-53 ED glass and will have even
better color correction.
The FS-128 is a very fine telescope but I wouldn't trade my AP 130EDT
for one.
Rich
ddd wrote in message <370d28d0....@news.texas.net>...
>On 5 Apr 1999 21:06:07 GMT, tmb...@aol.com (TMBack) wrote:
>
>> I'm talking about violet color correction. It is not
>>"utter BS."
>
>It is. Just how many side by side 5" comparisons
>have you done?
>
>> Now this _is_ utter BS. The transmission of an oil triplet
>>with the high transmission glasses that Roland uses,
>>and high quality multicoating puts the transmission above
>>the 97.5% to 98% mark. A fully multicoated Fluorite
>>doublet has transmission at 97+% in the visible. The
>>AP has the higher light transmission, but the difference
>>is not detectable to the eye (less than 1%).
>
>Again, an utter lie. I _have_ done side-by-side comparisons.
>With the same brand of EP used in both. The difference is there.
>
>You're not associated with Co. 7, are you? This is the
>type of outright lies that they are (in)famous for.
>
>> This statement is incredible It is at once contradictory,
>>and false. Just look at the last 5 years of S&T published
>>deep-sky photographs, and tell me what telescope has
>>the better photographic performance?
>
>This REALLY shows how ignorant you are of the market.
>S&T is hardly a showcase for good photographic work
>(although good photographs are occasionally published).
>I highly suggest you start looking around at what is produced
>before you star spouting off highly misleading propoganda
>to people looking for actual facts.
>
>And we all know how unbiased S&T is.
>
>> I have no such insecurity, as I have owned and used
>>both companies products. The comment about lying, is
>>not something I take lightly, Mr. Horr.
>
>Then print some factual information, not Co.7-type BS.
>
>To others:
>
>Remember the thread about the "AP Mafia" a few weeks
>ago and someone claimed to have never seen a "We
>will not allow the truth about AP to be spoken on the
>internet" type post? Well, here you go.
>
>I don't know why these types feel this need to do so,
>but I do try to put a few facts out on the newsgroups
>(as radical and idea as people seem to find it).
Ratboy99
rat
~( );>
Bob Luffel
Here's some of my own take on the Tak vs AP comparisons:
First off, the differences in real world performance of the Tak vs the AP is
going to be small for the majority of folks. In-focus comparisons on
planets, double stars, and deep sky viewing will likely show little
discernable difference to all but the most critical.
Unfortunately (ask my wife), I tend to be the over-critical type that
finds value in the extra bits of performance some scopes provide over
others. So, keep that in mind when interpreting any of my comments.
Also, many of the differences between scopes at this level of performance
and features have a large measure of personal preference involved in them.
I have owned and extensively compared/tested a number of Taks and
AstroPhysics scopes (Tak FC-65, FS-78, (2) FS-102, (2) FC-100, FS-128/ A-P
Traveler EDF, 155EDF), in addition to spending a fair amount of time
playing around and testing my friends versions of these scopes
(2 more Travelers, 130EDT, 155EDF).
Unfortunately, I haven't been able to directly set an FS-128 side by side
with a 130 EDT. But, I have been able to set a Traveler (f/5.8) right
next to some Taks (FS-102, FC-100). Part of the difficulty in comparing
such subtleties as a difference of a few percent (brightess, contrast)
is that the focal lengths of these scopes are all different, so magnification
differences must be taken into account and add some error.
In terms of color, some folks seem to be more or less sensitive or
critical of amounts of chromatic aberration. For some, the Tak doublets seem
to be almost color free. To others (like me), it is quite easy to see -
especially when compared to the A-P triplets (or a reflector). On a bright
star at magnification, there is a noticeable violet halo surrounding the
airy disk. On planets only the FS-128 showed a slight purple fringe/halo
(very slight), on the moon all my Tak doublets show it on the limb. This is
a very faint artifact (more noticeable is a slight yellowing of the image,
again a subtle but present effect).
What is debateable is whether this color error
has any real effect on low contrast planetary detail in most conditions.
My conditions (seeing) are typically not as good as those lucky folks
in Florida or Texas, so my in focus comparisons apply to more average
seeing (rarely better than a '7' here). In-focus I just don't see
a significant or repeatable difference in the planetary views through the Tak
100/102s versus the Traveler. I expect the FS128/130EDT will be similarly
similar...
I was able to detect very slightly fainter stars in the Traveler versus
the Taks (6% larger aperture, less air/glass interfaces). A difference
of a couple of percent is really insignificant, so the 128 vs 130 apertures
are lens transmissions are likely to be a moot point.
Optical quality wise, it all comes down to the actual sample you end
up with. I have not seen enough scopes from each manufacturer to make
any statistically valid comparisons about any particular model. However,
I have seen enough scopes from each manufacturere that I can start to form
some general opinions. Of the 7 Taks only one I found unacceptable
(an FS-102 that had excessive astigmatism). The 6 AstroPhysics were all
quite consistent, with the best scope I have ever tested being my Traveler (in
terms of spherical correction and smoothness). The Taks all were slightly
rougher compared to the AstroPhysics (not one Tak was the equal of any
of the AstroPhysics in this regard, but keep in mind that this is again
splitting hairs). On average, the spherical correction on the AstroPhysics
scopes was better (I won't try to quantify this, tho it is not hard to detect
when you learn to star test).
You will likely get an excellent
scope from either manufacturer. If you are more critical and demand
that last ounce of quality/performance then you will need to get some
help evaluating the star test. I do feel that your odds of getting
the 'best' optics are higher with the AstroPhysics (this is based on the
samples I have seen as well as other friend's comments to me).
Cooldown is one factor that might be important to you. The Tak doublets
cooled down somewhat faster than the A-P triplets. By this I don't mean
gross cooling effects (tube currents) which are similar. I mean that
last small bit of figure stabilization that is required to test the
ultimate wavefront past 1/4 wave.
So, based on my own experiences I think the visual performance of the
FS-128 and the A-P 130 will be quite close. The A-P is a little more
compact (the FS-128 has a fixed dewshield), which is nice on the
transport requirements. The focusers are very comparable, personal preference
is the rule here. Fit'n finish is high for both, though styles are
different (Tak is painted hardware, Astrophysics is polished and anodized).
My preference is the A-P, but I also like the Tak. I absolutely hate
the thread-on accessories of the Tak, you will most likely opt to spend
a few more $$ and get a 2" rear adapter.
I have to disagree with some earlier comments about photographic images.
The A-P scopes simply have better performance in the violet. My 155EDF
has fantastic images to the edge, absolutely no violet visible (as I would
expect, visually I see no violet halo either). I have not imaged with the
Taks, so I can't personally comment on those images (I have seen a number
of posted film FS-128 images that had some violet halos around
bright stars). The A-P scopes are also baffled properly for a larger
photographic field than the FS-128 (had a fully illuminated field diameter
of less than 0.5", versus approx. 2" field size for the A-P scopes, both
with the 2.7" focusers), if wide field astrophotos are your poison. I don't
know if Tak sizes the baffles in the 4" version of the FS-128 for a larger
fully illuminated field, maybe they do (the FS-152 with 3.5" focuser is
baffled for a larger field).
In terms of manufacturer support, I have to give AstroPhysics their due -
their support is tops, I have absolutely no complaints. They are
approachable and friendly. It is really nice to be able to deal directly
with the manufacturer (and designer) of the equipment. Televue falls
into this same class. Again, I don't have any statistical comparisons,
but I have personally experienced some grief with domestic Tak service and
know several other instances of poor experiences. I also know of plenty of
people that are happy with them, so keep that in mind.
Resale value of the A-P scopes are quite a bit better (stay flat
or go up in value). The FS-128 will drop somewhat (and is more expensive
to boot). The price of the A-P also includes a case (nice feature).
If a good friend asked me my recomendation, I would have to tell him/her
to go with the AstroPhysics if they can tolerate the wait (that really
is the deciding factor for many, the wait was sure worth it for me).
(So, I guess this makes me an official A-P Mafia member?)
If you can, I recomend buying a used FS-128 (already depreciated), put
down your deposit on the 130 EDF/T, and sell the FS when the A-P arrives
(and do your own comparison). You may find your interests change later,
anyways. At any rate, both are great 5" scopes and are a blast to use.
Bob Luffel
Ratboy99
>rat
>~( );>
>
First come, first served, right? (I'm not good at lotteries).
rat
~( );>
MHarveyWW1
Let me just add that I have been accused (vociferously....and by Roland
Christen himself!!!) of being an AP 'basher'.
I still maintain that I was unfairly accused! :)
And I owned several Takahashi FC model telescopes, including the FC-125 and
have compared several Taks side-by-side with numbers of AP's. I remain conviced
that the FC Taks were superior to the earlier AP's (yes there were quality
fluctuations on both sides of the issue). BUT....the current AP's are
certainly equal to, and probably superior to the FC's.........AND DEFINITELY
SUPERIOR TO THE FS SERIES.
Having used numerous examples of both series I have yet to find even one FS
that matches an FC. With its current offerings Takahashi has fallen from the
pinnacle of refractor-making.
My advice to you would be to hold your position in the AP delivery line. If
you simply cannot wait, then find yourself a good, used FC-125. There aren't
that many in the U.S. but they DO show up from time to time. Put an ad in
AstroMart and you'll probably get a line on one. Dan Gordon at SPECTRA
AstroSystems usually has a feel for the used Tak market and may know of an
owner who's selling. You might give him a call.
Mike Harvey
Todd Gross
Rich N.
not agree with you about APs and Taks. You call them
the "AP Mafia" and "AP bigots foaming at the mouth?.
You're sounding more like a troll with each post.
Rich
>You're full of cr*p. Name one post where I've bashed AP. You
>might want to read my post again. It would help you to keep from
>making a fool of yourself.
Rich N.
ddd wrote in message <3710021a....@news.texas.net>...
-snip
>The "AP Mafia" types are running around foaming at the mouth
>screaming "Tak - BAD!, AP - GOOD!" despite all of the evidence
>to the contrary and start raving if anyone dares point out that in
>fact the OTAs are very comparable.
>
Gene are you reading some other ng?
-snip
>
>I can't argue with that. I'll add to that - spend a couple of hundred
>dollars and go to a major star party and for gosh sakes do the
>comparisons oneself! That way they'll see through all of the idot's
>hyperbole and decide for themself which OTA meets their needs
>better.
TAC star parties are *free* and on a good night it isn't unusual
to see several of Astro-Physics and Takahashi refractors. You
can see several major brands of big Dobs, fine home made
Dobs, Tak, Meade, and Celestron SCTs, Intes, Questar and
Meade Maks, etc. http://www.seds.org/TAC/
Come on out Gene you might have a good time.
Rich
lude...@my-dejanews.com
tmb...@aol.com (TMBack) wrote:
> Gene Horr wrote:> >
> >Visually the Tak has a slight edge, due to the higher
> >light transmission. But it is avery slight edge, and
> >personally I would not use this as a deciding factor.
>
> with the high transmission glasses that Roland uses,
> and high quality multicoating puts the transmission above
> the 97.5% to 98% mark. A fully multicoated Fluorite
> doublet has transmission at 97+% in the visible. The
> AP has the higher light transmission, but the difference
> is not detectable to the eye (less than 1%).
Hi Thomas, this info I can fully confirm. Some years ago we have follow
scopes side by side a, Zeiss APQ 130/1000 (oiled triplet) and Tak FC
125/1000. The Zeiss showed an clearly visible , but only faint, brighter
image on all objects. b, Zeiss APQ 150/1200(oiled triplet) and Takahashi FCT
150/1050. No visible diffrence in brightness for the eyes. The Tak was an
triplet airspaced with noncoated Fluorite, but the lightloss against the
Zeiss was such small, that it was not visible.It was to all observers an
fully Identical view. Markus
>
> Thomas Back
>
-----------== Posted via Deja News, The Discussion Network ==----------
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
Rich N.
ddd wrote in message <371346c3....@news.texas.net>...
>On Tue, 6 Apr 1999 09:40:19 -0700, "Rich N." <rn...@znet.com> wrote:
>
>>ddd wrote in message <3710021a....@news.texas.net>...
>>-snip
>>
>>>The "AP Mafia" types are running around foaming at the mouth
>>>screaming "Tak - BAD!, AP - GOOD!" despite all of the evidence
>>>to the contrary and start raving if anyone dares point out that in
>>>fact the OTAs are very comparable.
>>
>>Gene are you reading some other ng?
>
>And because of that I am an "AP Basher". I've seen the same
>thing happen on the private mailing lists. If anyone dares mention
>that any other refractor is as good/better than AP they are instantly
>attacked without mercy.
Gene, look again at this thread. You call it an attack if anyone
has a different opinion on Taks and APs. You go on to label
them "AP Maffia".
>>>I can't argue with that. I'll add to that - spend a couple of hundred
>>>dollars and go to a major star party and for gosh sakes do the
>>>comparisons oneself! That way they'll see through all of the idot's
>>>hyperbole and decide for themself which OTA meets their needs
>>>better.
>>
>>
>>TAC star parties are *free* and on a good night it isn't unusual
>>to see several of Astro-Physics and Takahashi refractors. You
>>can see several major brands of big Dobs, fine home made
>>Dobs, Tak, Meade, and Celestron SCTs, Intes, Questar and
>>Meade Maks, etc. http://www.seds.org/TAC/
>>
>>Come on out Gene you might have a good time.
>
>Well, it would still cost a couple of hundred dollars (I should
>have stated that I was throwing in traveling money for those
>that don't live near a major star party). The point I was trying
>to make (and somewhat failing to do so) is that spending 5
>percent of the purchase price to try out a (for me) very expensive
>product. Even this won't give you the whole picture, you need
>to take some photographs to see how it will really perform
>(unless one is looking at buying for just visual work - a waste
>of money in that case IMO <ducking and running> <g>). But
>since most astrophotographers always have their albums
>at hand, you should be able to at least see the results of
>other's work with these instruments.
There are several fine astrophotographers in TAC. Come
have a look.
Rich
>Whenever I am in that region of the country I will attend one
>of your star parties.
TMBack
>Look at Thomas Back's claim of a dramatic contrast
>difference between the two instruments, when no one
>else has ever been able to see this.
Not only are you a very unpleasant person, not too
well informed, but now you are putting words into
my mouth. I never said that there is a "dramatic contrast
difference" between the Tak 128 and the AP 130.
What I said was that the AP 130 has better chromatic
aberration control (this is a fact -- you can believe it
or not), and that the better a lens is corrected for
chromatic aberration, the higher the contrast, and the
better the color purity. If this was not the case, what
would be the point in making apochromatic lenses?
Thomas Back
TMBack
>Your exact words:
>
>>The other point to consider is that the large violet halos
>>(even if they are not visible in viewing a planet), wash
>>the contrast down and act like a yellow filter.
I stand by this comment. A large violet halo will "wash
the contrast down and act like a yellow filter." Which it
most certainly does. Where do you find the words "Tak"
in this statement, or that I'm implying that there is a
quantifiable amount of contrast loss? If you read my post
more carefully, would have noticed I said (and you
conveniently left off):
>> wash the contrast down and act like a yellow filter.
If anyone doubts this, just setup a Meade ED and a
Newtonian side-by-side, on Jupiter <<
I mentioned Meade ED refractors, not Tak. You are
boring me Gene.
Thomas Back
Robert Berta
the AP....both are obviously inferior to my 8" SCT....and I think that you
should take advantage of the fact I would be very happy to relieve you of your
poor products by allowing you to trade up to a superior instrument. I won't
even charge you a premium upgrade price!
Bob
Rich N.
ddd wrote in message <371a6a4b....@news.texas.net>...
>
>>The other point to consider
>>is that the large violet halos (even if they are not visible
>>in viewing a planet), wash the contrast down and act like a
>>yellow filter.
>
>contrast between the two instruments despite the "washed
>out contrast."
One reason a friend got a Takahashi FS-128 is because
he prefers the warmer look it gives planets.
>
>Hmm. Seems a bit of a credibility problem. Can't you even
>remember which misinformation you spout off day to day?
>Or are you retracting your original post?
I don't see any credibility problem with Mr. Back's statement.
Why do you continue be inflamitory with comments like
"spout off day to day"?
I'm not going to continue this with you.
Rich
RMOLLISE
No! Wouldn't dream of letting you part with your wonderful SCT! I...I think I
can round up an LX-10 or two in return for those truly nasty (and flame
inducing) APs and Taks...believe me boys ya'll will be better off without the
heartache, and I'll see those puny refractors find a good home...somehow! :-)
Peace,
Rod Mollise
Mobile Astronomical Society
http://members.aol.com/RMOLLISE/index7.html
The Home of _From City Lights to Deep Space_:
Rod's Guidebook for the _Urban_ Deep Sky NUT!!
*********************************************************
Vahe Sahakian
>
> I have been waiting (money in hand) since last October to buy an AP 130. So
> far, the wait has been only to get on the official Astro Physics waiting
> list...where I will wait another 12 to 18 months or more before I will ever
> the next Astro Physics production run. AP tells me that they may use a
> lottery system to select new buyers! I confess that my resolve (very strong
> about 6 months ago) is starting to falter. I've dreamed of owning a
> wonderful instrument like this for years, but this waiting is a killer!
>
> Recently, I have considered abandoning the idea of buying an AP in favor of
> buying a more readily available scope such as a Takahashi. I know very
> little about a Takahashi and hope that some of you may provide me with some
> of your experience. My question is this: What would I be giving up (if
> anything) if I purchased a Takahashi FS-128 rather than an Astro Physics 130
> EDT? Any information that you may pass on will be appreciated and most
> helpful...thank you for your time.
Hi Al,
My two cents worth of opinion regarding the choice between AP130 and 5"
Takahashi:
There are indeed small differences but both are excellent scopes. At
this high level of performance you will not be disappointed with either
scopes regardless of what optical experts say.
I would point out one important consideration if you are considering
any of the 5" refractors for planetary use, based on my personal lessons
learned, I would say that if you must have a refractor, then a 6" apo is
about the minimum size for any serious planetary work if you are
expecting fine detail. This may sound strange when you consider what
J.R. Freeman was able to do with his 55mm "Refractor Red".
There is simply no substitute for aperture, quality alone will not do
the job, so if you are willing to take the plunge get something that
will save you the hassle and expense of future upgrades.
Regarding the 5" Tak.: For the longest time the 5" Tak was the largest
"affordable' fluorite and was the preferred planetary scope for all
Takahashi fanatics, the larger 6" fluorites, FC and FCT's, available
then carried astronomical price tags, therefore very few could afford
them. With the introduction of "cheaper" FS152 priced around 9K, large
number of 5" owners started to move up to 6" practically flooding the
market with good used 5" scopes. If you decide to settle for the 5" Tak,
you should be able to find a good one and save big money.
Good luck
Vahe
RAnder3127
> I have 3 AP OTAs and 3 Tak OTAs.
Woah! It must look like a missle battery
in your backyard! Congratulations as it
sounds like great fun!
-Rich
Death to Divx; Long Live DVD!
"If Tandy (Radio Shack) or Blockbuster
(who censor videos) adopt Divx, please
boycott them. Divx is Evil incarnate."
RAnder3127
(MHarveyWW1) writes:
> With the exception of Gene's...you've gotten some good advice.
> Let me just add that I have been accused (vociferously....and by Roland
>Christen himself!!!) of being an AP 'basher'.
>I still maintain that I was unfairly accused! :)
Forget to kiss his ring? :)
RAnder3127
writes:
>> I have carefully compared the Tak FS-128 (and
>>owned a Tak FS-102), and I can assure you that the
>>Astro-Physics 130mm EDT has significantly better color
>>correction than the 5-inch Tak.
>
>This is complete and utter BS. I have compared the
>two with _more_than_one_sample_ from each brand.
>If you pick any two at random about half the time the
>Tak will show _very_slightly_ more colour, the other
>half of the time the AP will. Essentially the quality is
>identical.
>
The adjectives from Mr. Back make it sound like
stars in the Tak are suffused in huge and noticeable purple
halos. Having looked through lots of the Tak's
poorer cousin (Vixen fluorites) I assume that
would not be the case, since the Tak would be
at least as colour free.
RAnder3127
>Spot diameters at 4358A are about 50 microns
>in the Tak, the AP are about 5x better in the new 5.1"
>f/8.3 EDT design.
So that's about 0.05mm on the film plane?
What is the intensity of the violet like when viewed
with the eye? That wavelength is pretty close to
the edge of human (average) perception. I doubt
it would make any difference for visual use.
Here's what Suiter says.
(BTW, this concerns the violet blur in an ACHROMAT which is far worse
than a fluorite doublet.)
Excerpt from Suiter's book, pg. 225:
"Violet is the furthest away (from focus), but that doesn't matter"
The human eye is not sensitive to violet except at high brightness,
so the defocused halo of violet light is mostly invisible."
The point is that unless you are doing hyper-critical photography,
it doesn't matter. And if your scope does work really well for
photography, it JUST "may" not be optimized for visual work.
So, you are making mountains out of molehills.
Given your knowledge of optics, why would you make
such a case for a non-issue like residual violet scatter
in a fluorite scope?
> Now this _is_ utter BS. The transmission of an oil triplet
>with the high transmission glasses that Roland uses,
>and high quality multicoating puts the transmission above
>the 97.5% to 98% mark. A fully multicoated Fluorite
>doublet has transmission at 97+% in the visible. The
>AP has the higher light transmission, but the difference
>is not detectable to the eye (less than 1%).
Are you absolutely sure of these figures? How thick is the
AP lens since it has three elements? The loss through
it is only 1-1.5% from 400 to 700 nm? If so, that's really
good.
> This statement is incredible It is at once contradictory,
>and false. Just look at the last 5 years of S&T published
>deep-sky photographs, and tell me what telescope has
>the better photographic performance?
Although that will give you a rough idea of performance,
you can't seriously think you can derive complete performance
characteristics from magazine photos, do you? In the first
place, most of them are 2" across. A middle-road consumer
digital looks good at that size. Second, there are far fewer
Tak 128's that i've seen used for photographs in S&T so
you don't have nearly the number of shots to compare.
Third, none of the shots is identical so I really don't see
where it can prove anything. The fact there are MORE
shots done on AP's "might" prove they are better, but
because of the big price difference (in favour of the AP)
that isn't even a sure bet.
WHALEN44
two instruments despite the "washed" out contrast.">>
Gene,
I think you are way off base here. You must be part of the "TAK" Mafia :). As
an owner of a Tak, how independent are you? I have never owned either of the
scopes in question, or any other models from these two fine manufacturers. I
have however had the chance on several occasions to view through products from
both companies, and on one occasion both 5" models side by side. My findings
were:
1. Image brightness - same
2. Image sharpness - AP
3. Focuser feel - Tak
4. Contrast - AP
There were no large differences, only slight. However the AP seemed to offer a
cleaner true color image of Jupiter than the Tak. In fact when I compared the
AP to a Newtonian, Jupiter was the same color. The Tak gave it a slightly
warmer shade. I would not hesitate recommending a Tak to anyone who needs a
premium APO in a hurry, in that they are the only game in town. However if the
buyer did not mind the wait, or had to have the very best available, I would
recommend the AP.
Also the AP's seem to have much better resale value in this country. Always
something to think about.
At the same time I must say that not all AP's or Taks are created equal. I do
think however that you have better chance of getting an excellent AP than an
excellent Tak.
I, like Mike Harvey, think the FC series Taks are better than the FS series. At
the same time, I prefer the EDF series AP's over the EDT's.
Richard Whalen
whal...@aol.com
Time spent observing the heavens is not deducted from your lifespan
Ratboy99
>Yet it is funny how no one else can see any difference in
>contrast between the two instruments despite the "washed
>out contrast."
>
>Hmm. Seems a bit of a credibility problem. Can't you even
>remember which misinformation you spout off day to day?
>Or are you retracting your original post?
>
>Gene Horr
>trarubee ng fjoryy qbg arg
rat
~( );>
Sue and Alan
I have known Thomas Back for quite a long time now. He is a rare person - a
very serious observer who has taken a strong interest in telescopes and
optical design. There are few people whose knowledge or experience I have
more respect for. I have absolutely no doubt that Thomas would not hesitate
to let us and Roland know if he found a scope he thought was superior to
what AP offers.
I only know you from your posts here on s.a.a., and your general tone does
not help your credibility. There is a big difference between calling
someone a liar and saying that you disagree with them. In my experience,
people often resort to name calling when they are unable to provide any
facts to back up their claims.
Clear skies, Alan
Kevin Wenker
Your opinions would be taken a bit more seriously if you left out the personal
attacks and venom. Maybe add a bit more fiber to your diet.
Kevin W.
ddd wrote:
> On 5 Apr 1999 21:45:39 GMT, cmudu...@aol.com (CMUDUDE101) wrote:
>
> >Lets see..... Thomas Back...... Gene Horr....................
> >
> >Ive heard of Thomas Back, and know of his optical knowledge.... Ive NEVER heard
> >of you Gene Horr, but the past few weeks iv read your posts all you seem to do
> >is bash astro physics. Whats with that?
> >As for the comparision, Ive heard from countless others they would rather have
> >the AP over the tak <this also includes 128 owners. myself included!>
>
> Sean:
>
> You're full of cr*p. Name one post where I've bashed AP. You
> might want to read my post again. It would help you to keep from
> making a fool of yourself.
>
> Gene Horr
> trarubee ng fjoryy qbg arg
>
> ROT13 to reply
jjgoss
T. Back has done this before, and always runs to his optical design program
or maybe his buddy Roland Christen will pull his butt out of the flames.
You will not get 100% objective advice about scopes from this group who
are certain that color error is higher in the Tak. Let 'em prove it. BTW,
ask Todd Gross, he has an AP130 and has had 2 5" Taks, I believe.
In the end, you eyes are the ultimate test, since side-by-side comparisons
will show any differences.
J.Goss
ddd wrote in message <371c84c2....@news.texas.net>...
>On 6 Apr 1999 21:02:49 GMT, tmb...@aol.com (TMBack) wrote:
>
>>Horr wrote:
>>
>>>Your exact words:
>>>
>>>>The other point to consider is that the large violet halos
>>>>(even if they are not visible in viewing a planet), wash
>>>>the contrast down and act like a yellow filter.
>>
>> I stand by this comment. A large violet halo will "wash
>>the contrast down and act like a yellow filter." Which it
>>most certainly does. Where do you find the words "Tak"
>>in this statement, or that I'm implying that there is a
>>quantifiable amount of contrast loss? If you read my post
>>more carefully, would have noticed I said (and you
>>conveniently left off):
>>
>>>> wash the contrast down and act like a yellow filter.
>>If anyone doubts this, just setup a Meade ED and a
>>Newtonian side-by-side, on Jupiter <<
>>
>> I mentioned Meade ED refractors, not Tak. You are
>>boring me Gene.
>
>Ok, lets put in the whole post.
>
>> I have carefully compared the Tak FS-128 (and
>>owned a Tak FS-102), and I can assure you that the
>>Astro-Physics 130mm EDT has significantly better color
>>correction than the 5-inch Tak. There has been a lot of
>>talk lately on s.a.a., about "APO" doublets not showing
>>chromatic aberration, but it is quite easy to see with high
>>magnification and a bright star. The other point to consider
>>is that the large violet halos (even if they are not visible
>>in viewing a planet), wash the contrast down and act like a
>>yellow filter.
>
>Um, gee, looks like you're comparing the two here.
>
>But, since you now appear to be backing off of your
>claims, I'll ask you flat out - Do you now admit that there is no
>difference in contrast between to the instruments? Yes
>or No?
jjgoss
using Tak scopes that were just awesome.
J.Goss
TMBack wrote in message <19990406214010...@ng15.aol.com>...
> As anyone who has visited the Astro-Physics factory,
>and seen the 30x40-inch blowups of wide field deep-sky
>photography taken with AP scopes, well, if there is any
>doubt in your mind before hand, there will be none after
>you see the quality of these photos. They truly are in
>a class of their own -- absolutely awesome.
>
>Thomas Back
Glenmore F. Wong
>
> Its awful funny how the "AP Mafia" turns this into an AP
> bash.
>
>This probably has the AP bigots foaming at the mouth, but
> it is the simple truth.
>
> Gene Horr
> trarubee ng fjoryy qbg arg
I have compared a friends Tak FS128 to my AP 155EDF. Both fine views as
long as you don't mind a very slightly yellowish Jupiter. In my friends
own words, he described it as a "slightly warmer view". Everyone here
seems to be having a nice discussion. You are the one being
inflammatory and "foaming at the mouth". Keep dragging out that "AP
Mafia" chestnut and you'll soon have as much credibility as jjgoss.
glenmore
TMBack
or (ddd)
or JJGoss
or Gene Horr
or trarubee ng fjoryy qbg arg
wrote: :-)
>But, since you now appear to be backing off of your
>claims, I'll ask you flat out - Do you now admit that there
>is no difference in contrast between to the instruments?
>Yes or No?
Assuming both instruments have the same wavefront
quality in the peak visual green-yellow wavelengths, the
Astro-Physics will have the higher visual contrast.
Thomas Back
TMBack
>The adjectives from Mr. Back make it sound like
>stars in the Tak are suffused in huge and noticeable
>purple halos.
Bob Luffel wrote:
>For some, the Tak doublets seem to be almost color
>free. To others (like me), it is quite easy to see -
>especially when compared to the A-P triplets (or a
>reflector). On a bright star at magnification, there is
>a noticeable violet halo surrounding the airy disk
Bob's right on the money.
Thomas Back
Bob Luffel
Gene,
Actually, I primarily use my 155EDF for imaging use. It was after getting
it that I discovered how truly awesome it was at visual/planetary.
I still have to disagree with your comments on the film imaging
comparisons between the Tak doublets and the A-P triplets (EDF). I have
had some superb results with my 155EDF and medium format (6x7). I have
not had any results that suggest abnormally large star images of
bright blue stars. No haloes, and the central burned in cores of the
stars are consistent with what I expect to get with color film (the
film produces some internal halation by itself). If I compare equally
bright red and blue stars (bright stars, not faint ones) I just don't see
any difference in size or haloes (even in 11x14 enlargements).
I haven't used any Tak photo attachments, so I will certainly take your
word on how excellent they are. The camera attachments to the
AstroPhysics scopes are quite good and very well executed. They work
well in the dark and stay put. The 4" focuser on my EDF is like the
rock of gibralter - which is what it takes to properly hold a large
Pentax67 and field flattener in place. You can remove the whole
assembly and reattach it with absolutely no focus change. There is
virtually zero slop in the focuser and I can easily shift focus in
thousandth of an inch increments (I use a dial caliper to average
focus). Anyways, I think we are talking two very fine systems here
and some differences may matter based on personal taste. I would be
happy with the Tak setup, I am sure, as their other pieces are so
well done (I just don't like the visual adapters, and the clamping
eyepiece holder doesn't prevent the eyepiece from rocking - very bad
for use in a guidescope). I really like the A-P design and execution, it
just works for me so well and reliably.
Anyways, I would like to hear your opinions on the specific features
of the Tak photo attachments and what you find to be their strong
points. The item I most want to build for my EDF is a permanent dial
readout of focuser position (I have started to make one, but have not
finished it).
As I stated, I haven't done any photography with my Tak scopes for
a personal direct comparison. I have come across some images taken
through an FS-128 that seem to illustrate my points, though.
Quentin Hinds has taken some nice shots with an FS-128 and reducer, and
posted them on his website. A particularly telling image is found at:
http://lonestar.texas.net/~wqhinds/128_434.html
This is an image of the Horsehead nebula. I also took an image of the
Horsehead with my 155EDF on PPF400 last fall. My image goes quite a bit
deeper, and is sharper, but the main point of comparison are the bright
blue stars. In Quentin's image the stars (especially the brightest one)
are surrounded by a very large violet/blue glow (as you pointed out in
your post). In my EDF shots, I see absolutely NO such glow and the
burned in area of the star is similarly sized to the Tak photo despite
being quite a bit deeper shot. Of course, the resolution of my image
is better and much more extended nebulosity is captured (though my
exposure was effectively a tad shorter at 70 minutes at f/7 and Quentin's
is 50 minutes at f/5.6, probably due to film differences).
If you wish, I can post a low res image of my horsehead shot to my
brother's website so you can compare yourself. If you know of any
other valid comparison shots I would like to look at them also.
Another less dramatic comparison can be made by comparing Quentins
M42 shot to one done by Wallis and Provin (http://voltair.csun.edu/m42.html).
If you look closely you will see that the brightest blue stars in these
shots are tighter in the A-P image. The difference is not that pronounced,
but the tighter stars are found in the A-P image. (look at the brightest
star in the field, note that it is merging with an adjacent fainter star
in the FS-128 image, but there is dark sky separating them in the A-P
image). Both are on Fuji film, and the color balancing is different,
but both display similar levels of faint detail.
While Quentin's shots are quite nice, the bloated blue/violet stars
of the Horsehead image are beyond my standards for this shot and this
would prevent me from considering that Tak as my astrograph of choice
(note, the FCT-150 is likely a different beast altogether and I would
expect it to compare much more equally to the 155EDF, hopefully I will
get to see one someday).
Sure, the film and processing differences between these images introduces
some variables - but the differences are gross enough that that alone cannot
explain the poorer performance of the Tak FS128 on bright blue stars. At
a minimum there is no way I can conclude that the A-P produces larger blue
haloes around bright blue stars (and my visual comparisons certainly
bear this out, the Taks have a noticeable violet halo and the A-P simply
has none). I fully expect that the 130 f/8 EDF will have even better
color correction than my 155 f/7 EDF, visually and photographically.
I feel there certainly is a reason that the 'Pinos Gang' uses the A-P
EDF, and it is for it's imaging capabilities. I also have plenty of other
acquaintances that use AstroPhysics gear here in Colorado and other
locations throughout the country. Perhaps most of the other
astroimagers in your locale use a different setup due to local
preference/influence (Texas Nautical is close by), which is understandable.
Nationally, this doesn't appear to me to be the case.
Also, I have to admit that I haven't seen many astrophotos published
in Astronomy/Sky&Tel taken by Tak scopes. The very best photos through
large refractors are consistently taken with A-P scopes (though, in Japan
I expect this is not the case!). There are reasons that domestically
the choice seems to gravitate to AstroPhysics - namely cost and
performance (certainly not availability...). I doubt any Mafia tactics
are to blame ;-)
Cost is certainly a factor to consider in the equation.
Here is a cost comparison between some photo configurations of
various Tak and AP scopes. The Tak prices are based on 80% of list
(this is the deepest discount I have seen on Tak gear). Each scope
includes a field flattener or reducer for medium format work and an
adapter for the Pentax 67.
$3725 - A-P 130 EDF w/ 2.7" focuser, field flattener for Pentax67, case
$4975 - Tak FS-128 w/ 2.7" focuser, matching reducer, Pentax67 adapter
$6111 - Tak FS-128J w/3.5" focuser, flattener, Pentax67 adapter
$6800 - A-P 155EDF w/4" focuser, flattener for Pentax67, carry case
$8991 - Tak FS-152 w/3.5" focuser, flattener, Pentax67 adapter
$14,879 - Tak FCT-150 w/large focuser and flattener, Pentax67 adapter
So, to my eyes (and wallet) I find that the AstroPhysics equipment offers
a superior (and lower cost) route for astrophotography with medium formats.
When I set out to put together the ultimate wide field astrophotography
rig I quickly found that the 155EDF was, for me, the clear choice.
(I have done narrow fields with a C14 for many years and wanted to
do some medium format wide field photography). If there were no
AstroPhysics, I would likely have gone with a Tak.
Again, this does not mean
that the Tak FS's aren't capable astrophoto instruments - I think your
results and Quentin's attest to this. I just disagree that they offer
any advantage over the AstroPhysics equipment (rather, I see it as the
other way around), and would recomend anyone interested in serious
wide field/medium format photography give the AstroPhysics serious
consideration.
Not to change the topic,
that BRC-250 sounds like quite an instrument! - how about sharing some
of your results with it?
Bob Luffel
AstroJLyon
>>EDT? Any information that you may pass on will be appreciated and most
>>helpful...thank you for your time.
>>
>>
>>
>
>there is very little difference, almost identical. There is a tad, and I mean
>
>a "tad" more color in the TAK, and it is a longer tube. It is stupendous, and
>
>should be considered. Also, I have heard of more quality control issues
>compared to A/P, but if you know what you are doing (star test, etc), you
>can't lose.
>see http://www.weatherman.com for a rundown on both scopes
>Todd
>
>
Todd:
I read the review on your web page but it was of the 130mm EDF, not the 130mm
EDT, which was Al's question. These are not the same telescopes. The EDF is an
f/6 while the EDT is an f/8. They use different glass types, although the new
EDT will use the same glass as the EDF. Perhaps you should get one of your
mentors to explain it to you :).
Also, on your web page you said you have been in astronomy for over three
decades. It is surprising then that you need so many mentors :). Perhaps it's
because you dropped out of the hobby in the early 1970's and just recently got
back in.
I followed the link on your web page to Ed Ting's web page, where I read his
excellent review of the 130mm EDT (Al should check it out). Ed should be
congratulated for his reviews. His they are in-depth, accurate, and well
balanced.
Sincerely,
John Lyons
TMBack
>So that's about 0.05mm on the film plane?
Just a little under the width of a human hair at
the focal plane. However, the violet h-line is much
larger yet - about 100 microns in the Tak FS-128.
>What is the intensity of the violet like when viewed
>with the eye? That wavelength is pretty close to
>the edge of human (average) perception. I doubt
>it would make any difference for visual use.
Incorrect. The eye is quite sensitive to blue/violet
light under scotopic conditions. At 4358A, it has about
a 25%+ relative luminosity factor vs. the peak sensitivity.
In other words, quite visible.
>Here's what Suiter says.
Please, don't quote Suiter on refractors. Suiter is
a smart guy, but his book really missed the boat when
it comes to testing and his analysis of them.
>"Violet is the furthest away (from focus), but that doesn't
>matter" The human eye is not sensitive to violet except
>at high brightness, so the defocused halo of violet light is
>mostly invisible."
Yes, at the violet h-line (4047A), but not from 4358A
to 4861A, where (see above) the eye is still quite
sensitive.
>So, you are making mountains out of molehills.
>Given your knowledge of optics, why would you make
>such a case for a non-issue like residual violet scatter
>in a fluorite scope?
A non-issue? Defocused violet and spherochromatism
in the same spectral region does make a difference.
With this logic, we might as well go back to achromats.
>Are you absolutely sure of these figures? How thick is
>the AP lens since it has three elements? The loss
>through it is only 1-1.5% from 400 to 700 nm? If so,
>that's really good.
You bet I am. Get a hold of the Schott or Ohara master
glass catalog. Guess what the transmission is for FPL-53
glass through a 10mm piece? .994% (4000A), .999% at
5500A to .997% at 8000A. For BK-7, it is even higher.
If anything, my transmission numbers are conservative.
Air-to-glass surfaces (even if multicoated) lose much
more light.
>Although that will give you a rough idea of performance,
>you can't seriously think you can derive complete
>performance characteristics from magazine photos, do
>you?
As anyone who has visited the Astro-Physics factory,
AstroJLyon
newsgroup for a year or so but during that time Bob Luffel and Tom Back always
sound like they know what they are talking about. I'd take their word in this
one (by the way, I don't own either a Tak 128mm or AP 130mm but I wish I did!).
Sincerely,
John Lyons
Ratboy99
>or JJGoss
>or Gene Horr
>or trarubee ng fjoryy qbg arg
>wrote: :-)
>or JJGoss
Bingo Mr. Music
rat
~( );>
Todd Gross
Todd Gross
samw...@my-dejanews.com
blu...@gr.hp.com (Bob Luffel) wrote:
> $6800 - A-P 155EDF w/4" focuser, flattener for Pentax67, carry case
>
> $8991 - Tak FS-152 w/3.5" focuser, flattener, Pentax67 adapter
>
> $14,879 - Tak FCT-150 w/large focuser and flattener, Pentax67 adapter
Really have enjoyed the technical discussion here. Must admit though that if
an air spaced fluorite doublet provided a better astrographic or visual image
than an oiled ED triplet, that Roland would probably be building them, don't
you think?
The key to me is the above price comparison provided by Bob Luffel. I would
compare my EDF with all the goodies to the Tak FCT-150. Even with different
guys running the design software, I can't help but think the overall
correction of these two telescopes for either visual or astrographic use must
be more similar than the doublet/triplet comparison. The value of the AP
refractors was further demonstrated when my brother picked a 130 EDF up on
SciBid for $4250. A premium price for this OTA, yet he saved $800 over an
FS128. He feels he got a great bargain. :-}}
And I have the best of both worlds so winning here doesn't matter to me. I
love my Tak FC100 and the Traveler EDF is a kick to boot!
Finally, I have one of Luffel's EDF images on my wall. It's the classic
Lagoon- Trifid area. I could only find one star with any sort of weak halo
(blue) out of about 2 billion. :-}}
Until AP pricing gets more realistically tuned to the market, the only really
question here for 99% of the purchasers of one or the other of these
telescopes is wait for the AP and save money (a rather large amount by my
subtraction) or buy the readily available Tak FS with less performance, or
maybe wait a bit for the FCT by comparison.
Stew
-----------== Posted via Deja News, The Discussion Network ==----------
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
Shedir
>I notice you go to extreme lengths to avoid actually
>denying), then the only correct conclusion is that (a)
>your argument is wrong, or (b) the Tak actually does
>show better colour correction.
>Gene Horr
You forgot about conclusion (c) Gene. That your observing skills and
knowledge of optics is just not up to the level of Thomas Back .
Robert
Bob Luffel, Thomas Back, and Stew Squires have all given me outstanding advice
and infinite help when finding my way in the astronomy world.
Bob successfully convinced me to dedicate my life to exchanging smallish green
pieces of paper for the most amazing feats of optical engineering I've
encountered.
I am a member of the AP mafia. I am only a hit man at the moment, but I'm
shooting for a promotion.
I love Takahashi too, but with multiple AP scopes (I'm hoping AP will hurry up
and make more), I find going with all one manufacturer or the other makes the
most sense for accessory maximization.
I think they each have their benefits:
Taks are:
1) Light weight
2) Fast cooling
3) Available
4) Excellent values in the 78mm, 102mm, and 128mm iterations
AP's are:
1) Surreal
2) Difficult to buy (time if new, money if used)
3) Don't forget surreal
In closing, I think both scopes have a place.
I have to thank Bob Luffel, Thomas Back, Stew Squires, and of course Roland.
They have all helped a relative neophyte find perfection.
Perfection is a rare thing, if you see it, grab it.
Thanks,
Rob
Rich N.
http://home.earthlink.net/~dvj/ . John Gleason's
astro photos have been published is the astro mags.
I have had the pleasure of seeing his prints in person and
they are so good you can look at them over and over
again and find new things of interest.
I believe most of these astrophotos were taken with
a 155EDF and some with a 180EDF
It was looking through John's 155EDF with an AP/Zeiss
binoviewer that convinced me to get a binoviewer. I had
looked through other binoviewer several times before but
it was looking through John's at several deep sky objects
that made buy one.
Rich
RAnder3127
>Really have enjoyed the technical discussion here. Must admit though that if
>an air spaced fluorite doublet provided a better astrographic or visual image
>than an oiled ED triplet, that Roland would probably be building them, don't
>you think?
Roland doesn't seem to like fluorite.
Ratboy99
>
>It is pitiful.
>
>Gene Horr
>trarubee ng fjoryy qbg arg
>
Well, at this point I will buy the fact that you are not him...But you are
certainly goofy enough to be.
rat
~( );>
TMBack
>Good try, kid.
Wish I was a kid again. Age sure does creep up on
all of us.
>When you actually accomplish the fifth grade
>capability of reading headers, then maybe you can get
>someone to listen to you.
Gene, you must be a very angry, frustrated man. The
header quote was a joke, lighten up.
>But since all that you are doing is compounding
>the examples of the things that you are ignorant of....
Ignorant? Hardly.
>But since it doesn't have a higher visual contrast (which
>I notice you go to extreme lengths to avoid actually
>denying), then the only correct conclusion is that (a)
>your argument is wrong, or (b) the Tak actually does
>show better colour correction.
Are you daft? How clearer can I make it? The Astro-
Physics has the higher contrast. That's not to say that a
good example of a FS series Tak is a poor instrument, and
I never said so. In fact, I know of three superbly figured
FS Taks: Bob Luffel's FS-128s, Dave Pisak's FS-152 and
Chuck Gulker's FS-78. Color correction, however, is
not as good as the corresponding AP apochromats, but
they are superb instruments. All three would agree.
My luck was not so good, and my dealings with your
"Buddies," were not any better with my purchase of
a new Tak FS-102. Spherical and chromatic correction
was poor, and I at once returned the instrument. I agree
completely with Mike Harvey's assessment that the older
FC series was superior. Three of my friends FC-100's
had as close to a perfect figure as I have ever seen in a
small apo refractor.
I want to thank Bob, Rat, Shedir, Sean, Rich N, Kevin,
Alan, Markus, Todd, and Robert for their kind words,
and above all, Roland Christen for the wonderful
telescope he has made for me.
Thomas Back
Ratboy99
right? Why don't you try exercising a little courtesy when communicating with
your peers on the internet. It's a little difficult to get people to see things
your way when they are under attack. As for Goss: No offense Goss, you've
been a regular gentleman lately.
rat
~( );>
Dave & Frani Pisak
TMBack wrote in message <19990407193008...@ng12.aol.com>...
> Are you daft? How clearer can I make it? The Astro-
>Physics has the higher contrast. That's not to say that a
>good example of a FS series Tak is a poor instrument, and
>I never said so. In fact, I know of three superbly figured
>FS Taks: Bob Luffel's FS-128s, Dave Pisak's FS-152 and
>Chuck Gulker's FS-78. Color correction, however, is
>not as good as the corresponding AP apochromats, but
>they are superb instruments. All three would agree.
>
Hi Tom,
I really couldn't be happier with my FS152, you're right it
is superb, but you know if Roland would be good enough to
make me a new 180EDF, I would jump at it despite the big
(for me) financial hit!
Dave
Chuck Gulker
higher contrast. That's not to say that a
good example of a FS series Tak is a poor instrument, and I never said so.
In fact, I know of three superbly figured
FS Taks: Bob Luffel's FS-128s, Dave Pisak's FS-152 and Chuck Gulker's FS-78.
Color correction, however, is
not as good as the corresponding AP apochromats, but they are superb
instruments. All three would agree. >>
Hi Thomas. No question that my 5.1 EDT F8 has less color than my FS-78.
This
would be for both in, and out of focus situations, with any eyepiece, at any
power. For all practical purposes, the 5 is visually color free, while the
3 has
only the very slightest of color at high power. The Tak 78 is a fine little
scope which is
a joy to use. It star tests nicely and holds high powers extremely well.
Take care, Chuck
Rich N.
Rich N. wrote in message <7egn6c$r6f$1...@remarQ.com>...
Just a little nit pick of my post. The images of deep sky
objects through John's binoviewer are the first thing that
come to mind but really the thing that pushed me over the
edge to get the binoviewer was looking through his bino-
viewer at Jupiter. Without the binoviewer I could see an
irregular white area in the lower part of the SEB. With
the binoviewer that white area was clearly several white
ovals.
Rich
jjgoss
You've been your typical repulsive self. Keep up the good work, you are
a fine example of how not to behave on the Internet. So, too, is Thom.
Back, among others of you...
J.Goss
Ratboy99 wrote in message <19990407193735...@ng-ch1.aol.com>...
Chris1011
Roland doesn't seem to like fluorite.
-Rich
>>
Our 90mm f5 3 element scopes have a fluorite center element. After working 60
sets of pure fluorite, I vastly prefer FPL53. The workability is much better.
Roland Christen
rpr...@my-dejanews.com
>
> I still have to disagree with your comments on the film imaging
> comparisons between the Tak doublets and the A-P triplets (EDF). I have
> had some superb results with my 155EDF and medium format (6x7). I have
> not had any results that suggest abnormally large star images of
> bright blue stars. No haloes, and the central burned in cores of the
> stars are consistent with what I expect to get with color film (the
> film produces some internal halation by itself). If I compare equally
> bright red and blue stars (bright stars, not faint ones) I just don't see
> any difference in size or haloes (even in 11x14 enlargements).
> As I stated, I haven't done any photography with my Tak scopes for
> a personal direct comparison. I have come across some images taken
> through an FS-128 that seem to illustrate my points, though.
>
> Quentin Hinds has taken some nice shots with an FS-128 and reducer, and
> posted them on his website. A particularly telling image is found at:
> http://lonestar.texas.net/~wqhinds/128_434.html
>
> This is an image of the Horsehead nebula. I also took an image of the
> Horsehead with my 155EDF on PPF400 last fall. My image goes quite a bit
> deeper, and is sharper, but the main point of comparison are the bright
> blue stars. In Quentin's image the stars (especially the brightest one)
> are surrounded by a very large violet/blue glow (as you pointed out in
> your post). In my EDF shots, I see absolutely NO such glow and the
> burned in area of the star is similarly sized to the Tak photo despite
> being quite a bit deeper shot.
> Another less dramatic comparison can be made by comparing Quentins
> M42 shot to one done by Wallis and Provin (http://voltair.csun.edu/m42.html).
> If you look closely you will see that the brightest blue stars in these
> shots are tighter in the A-P image. The difference is not that pronounced,
> but the tighter stars are found in the A-P image. (look at the brightest
> star in the field, note that it is merging with an adjacent fainter star
> in the FS-128 image, but there is dark sky separating them in the A-P
> image). Both are on Fuji film, and the color balancing is different,
> but both display similar levels of faint detail.
>
> While Quentin's shots are quite nice, the bloated blue/violet stars
> of the Horsehead image are beyond my standards for this shot and this
> would prevent me from considering that Tak as my astrograph of choice
> (note, the FCT-150 is likely a different beast altogether and I would
> expect it to compare much more equally to the 155EDF, hopefully I will
> get to see one someday).
>
> Sure, the film and processing differences between these images introduces
> some variables - but the differences are gross enough that that alone cannot
> explain the poorer performance of the Tak FS128 on bright blue stars. At
> a minimum there is no way I can conclude that the A-P produces larger blue
> haloes around bright blue stars (and my visual comparisons certainly
> bear this out, the Taks have a noticeable violet halo and the A-P simply
> has none). I fully expect that the 130 f/8 EDF will have even better
> color correction than my 155 f/7 EDF, visually and photographically.
> Bob Luffel
======================================================================== This
is a very interesting point that was discussed sometime back with regards to
comparisons between images taken with a Meade 6 inch refractor and an AP 6
inch EDF. The same kinds of points were made at that time also, i.e. the
Meade images displayed large blue halos around bright stars while the AP did
not. The two images in question can be seen at: voltaire.csun.edu/m42.html
and at: www.galaxyphoto.com/jwm42.jpg. The point was that the AP triplet had
better color correction than a ED doublet as evidenced by color photography.
At the time, some one through private email, suggested to me that the
differences in the images was exclusively the result of differences in film
types and in image processing. This idea seemed plausible, so I decided to
put it to a test. To briefly summarize, I rescanned my negative (taken with
my EDF) and try as I might, altering color balance, saturation and just about
every other factor that I could think of, I simply could not get a scan that
displayed blue halos that were as prominent as thoughs seen in the ED doublet
image. It is possible that differences in film type could account for the
halos, but I doubt this also simply because one never sees these blue halos
in *any* EDF images. I am inclined to believe, based on this admittedly
incomplete evidence, that the absence of these halos in the EDF images is
really the result of better color correction. Bob Luffel's analysis seems to
me to be right on the money....
Best,
Robert Provin
Stard...@webtv.net
end optics, I'd like your opinions. How do the images in Mak-Newts
compare to APOs? I have a hard time taking magazine reviews at face
value, but the Mak-Newt design seems promising. Also, would an AP900
mount be able to carry a 10" or 12" Mak-Newt if such a scope exists?
Would the FOV in a f/6 Mak-Newt be the same as an f/6 APO?
Thanks for any opinions. Clear Skies!
Stard...@webtv.net (David M)
I love the night.The day is okay and the sun can be fun but I love to
see those rays slip away--Blue Oyster Cult
RAnder3127
(Chris1011) writes:
I'm "thermally" shocked! :)
RAnder3127
>I find going with all one manufacturer or the other makes the
>most sense for accessory maximization.
How many AP eyepieces do you own?
RAnder3127
the "Astronomy Mall" site. See if you agree or disagree.
Please forgive the <> junk, I copied the source.
-Rich
Number 1.
(Someone) asks about the difference between Orthos and Naglers as far as
sharpness and contrast.
Naglers are always sharper, anywhere in the field, including the center.
In general, eyepieces with less glass, like Orthos or the superior
Plossls can have a bit more contrast. However, it is difficult to make
fair comparisons: when an 82 deg. field is filled with sky background,
and 45 deg. Ortho is seen with a large black "outer-field" beyond the 45
deg., you may get an impression of greater visual contrast.
I'd consider our new 6 and 7 element Radian and Nagler Type 4s with their<br>
high index glasses and full multicoatings for maximum contrast. One<br>
owner says the Radians are comparable to his Zeiss Orthos in contrast,<br>
but have more field, eye-relief and sharpness. In general, the faster<br>
the scope, the bigger the differences.
Number 2:
(Someone) says newsgroup scuttlebutt says 7mm Naglers made in Japan are not as
good as our Taiwan made units. True?
Nonsense. Some people blithely confuse the manufactured origin of<br>
eyepieces and seem to delight in rewriting history to match a personal<br>
agenda.
We check every eyepiece at f/4 for diffraction limited performance. And<br>
even a Japanese magazine once commented that they though our Taiwan<br>
coatings were a bit better. No, "Tele Vue is not going downhill" as one<br>
post from a disgruntled dealer indicated, and no, we've never made<br>
eyepieces in China like the "big guys" do (unless you want to tag Taiwan<br>
as part of China). So thanks for asking here, rather than accepting<br>
on-line "guru garbage."
RAnder3127
>is a very interesting point that was discussed sometime back with regards to
>comparisons between images taken with a Meade 6 inch refractor and an AP 6
>inch EDF. The same kinds of points were made at that time also, i.e. the
>Meade images displayed large blue halos around bright stars while the AP did
>not.
All refractors will display this effect since none of them
are completely colour free. I do remember some of the
AP owners telling me blue halos around star images taken
with AP's and published in magazines weren't the result of
chromatic aberration. I guess they were wrong.
However, the colour only shows up when a star is a certain
brightness and the speed and exposure of the film is
long/high enough. Also, the specific film's sensitivity
to blue light plays a big part. But, the Meade will obviously
show the halo more easily than the AP.
-Rich
HC
when rephrasing my original question. Here is the e-mail that I sent
directly to the "Ask Al" forum:
Someone has commented on sci.astro.amateur that the new
"Made In Taiwan" Nagler 7mm eyepieces are optically not
as good as the old "Made In Japan" ones. Assuming the
design and manufacturing specs of the Nagler 7mm have
not changed, how can that be true?
And here is Al Nagler's response in its entirety:
Nonsense. Some people blithely confuse the manufactured origin of
eyepieces and seem to delight in rewriting history to match a personal
agenda.
We check every eyepiece at f/4 for diffraction limited performance. And
even a Japanese magazine once commented that they thought our Taiwan
coatings were a bit better. No, "Tele Vue is not going downhill" as one
post from a disgruntled dealer indicated, and no, we've never made
eyepieces in China like the "big guys" do (unless you want to tag Taiwan
as part of China). So thanks for asking here, rather than accepting
on-line "guru garbage."
Reminds me of another "guru" complaint, that some Panoptics are sharper
than others. More nonsense. Any optical design that is simply scaled to
different focal lengths (Tele Vue Plossls, Nagler Type 1, panoptics,
Wide-Fields) must have identical aberrations related to sharpness. Any
perceived differences are due to interactions with your eye (large exit
pupils, telescope obscurations for long focal length eyepieces) or
telescope optics limitations for shorter focal length eyepieces. And as
for possible manufacturing differences between samples, Forget it. It
just doesn't happen in our eyepiece production to a point where you can
visually see a difference.
I'll let you in on another secret. For a long time, our 13mm Nagler
(with the interesting patent title of "Ultra-Wide Angle Eyepiece") had
been made with an 84 deg. apparent field due to an enlarged field stop.
We reduced it to 82 deg to reduce the kidney bean effect, while still
meeting the advertised apparent field spec. So if ANYONE thinks that a
competing eyepiece is better than the 13mm Nagler because it has less
"kidney beaning," ask them to try enlarging the field stop to get up to
82 deg. and then compare.
mark dambrosio
amateurs. When we think that optical technology has reached the
pinnacle of achievement, possibly 5-10 years from now, along comes new
knoweledge, and new materials that could surpass what has been done
today. Perhaps one day we'll all look back, and say, "Yeah
this, and that were pretty good, but not like my new Super Duper APO
with XYZ-007 Glass!" It's an interesting thought! Mark
squi...@tar-palantir.com
rande...@aol.com (RAnder3127) wrote:
> How many AP eyepieces do you own?
> -Rich
Like me, Robert owns at least one set of the AP marketed Zeiss
orthos. And like me he probably owns one of the AP marketed
Zeiss binoviewers. He probably doesn't have one of the Carl
Zeiss 2X barlows, especially matched to the Zeiss 1.25 orthos,
but I got REAL lucky on that one.
Hellava system all put together Rich.
Stew
>
> Death to Divx; Long Live DVD!
> "If Tandy (Radio Shack) or Blockbuster
> (who censor videos) adopt Divx, please
> boycott them. Divx is Evil incarnate."
>
>
-----------== Posted via Deja News, The Discussion Network ==----------
Bob Luffel
Gene,
Ok, one last shot at this.
>This is very interesting. Do you have any high resolution (2000+
>dpi) scans? If so this will be the first AP that is able to do this
>and something that I know a lot of serious astrophotographers
>would want to know about.
Yes, the scan of my Horsehead Nebula image is a drum scan at much
higher resolution than 2000 dpi (a 120MB file...).
Have your astrophotographers take a look at John Gleasons horsehead
shot (see Rich N.'s earlier post). Pretty nice stuff (his shot looks
extremely similar to mine, though he uses a 180 f/7 EDF!, drool...).
>But one quick check - the halation menionted is red with PPF, right?
>If it is blue then it is not halation. It is the minor lack of
>correction I was referring to. PPF does not produce this artifact.
No, I was talking blue - perhaps it is not halation that is the cause of
the larger blue star images. I see this on virtually every shot of
the horsehead, even those from reflectors. Perhaps the cause is
some other scattering effect in the film or instrument (not halation,
per se?). Those are very bright stars, a real acid test.
I assume that PPF has an anti-halation layer, but why would it only
show up on the red layer? Any film experts out there?
In an M8/M20 image I have taken, there is a fairly bright blue star which
has a very slightly softer edge to it as well as a slightly
fainter white/red star which shows a somewhat fainter similar edge
appearance. I would say the blue star has this to a somewhat greater
degree, but it is subtle. Based on this, I inferred that it was
due to some scatter in the film (not chromatic error from the objective or
flattener). In any case, I don't find any large blue halos. Perhaps
some of the images you saw were poorly focused? (but I doubt this would
produce a very large halo).
>I haven't seen the AP 4" focuser. Could you post some pictures
>of it? The AP 2.7" focuser, which I've used numerous times, is
>a great focuser, but it is only for visual use! I don't know why
>they don't make the focuser adaptable for camera use (thread-
>to-thread).
Actually, the field flatteners for the 2.7" A-P focusers thread on,
so that may meet your desires already. The clear internal diameter of
the 2.7" focuser is, in fact, 2.7", so it works very well for formats
larger than 35mm, too. I would say that it is Very targetted at photographic
use!
>One question on the 4" focuser - how good is the camera angle
>adjuster? The new Tak 4" focuser is cr*p. Rather than use
>thread-to-thread they now use a slip ring with set screws and
>no longer offer a camera angle adjuster. This means you have
>to loosen the set screws to adjust the camera. I can't imaging
>a worse design for photography as you have the slight risk of
>not pressing the camera all the way in and having it "kinked"
>out of square by a few hundredths of an inch. Not that big a deal
>with 35mm, but this is 4" format for gosh sakes! You _will_ see
>the effects of an error at the edge of a 6x9 or 4x5 frame.
The A-P 4" focuser (4.3" at the inlet, but clear
aperture is around 4") uses a reverse dovetail groove, and an inset
brass compression ring that is compressed by two stainless thumbscrews.
With one exception, it has always seated the flattener/camera firmly and
repeatably. It is not 100% foolproof, as I had one image (out of dozens)
that I must have gotten the assembly cocked enough that the two screws
did not fully seat the flattener assy - which resulted in the film plane
being out of square by a couple of thousandths. I tried to repeat this
in daylight, and under just the right conditions this could, in fact, happen.
All of my other 6x7 images show consistent focus at all 4 corners.
I now make a little more conscious effort to apply force to the flattener
when tightening the screws. (someday I will drill and tap for a third
clamp screw and nail this potential).
It is true that such large formats really test your ability to focus and keep
the film flat and square. There are other sources of errors that creep
in at these large field sizes (field rotation, film buckling, uneven
hypering, you name it). I am very pleased at the nearly 100% success rate
I have gotten with my system.
>I think that Takahashi has made a severe mistake with this new
>design. In the drive to cut weight they've almost eliminated the
>only material advantage over the AP design.
>Well, I covered somewhat of it above, but I'll add a few items. The
>old 4" focuser was built like a tank (but weighed like one also. The
>focuser alone must have weighed almost 30#.) It was silk smooth
>with zero image shift. The camera angle adjuster was built to the
>same tight tolerances. You could sit there spinning the camera all
>night, and the focus plane would never tilt. All of the attachments
>were thread to thread, with each format having a special attachment
>to make sure that the film plane was always within a few hundredths
>of an inch distance from the correctors. A _lot_ of thought went into
>this design.
>The negative aspect has been mentioned several times. Because
>each camera brand/format has a different film plane to mounting
>bayonet distance, each camera type had to have its own special
>adapter, leading to the confusing looking system charts that you see
>everyone complain about. This attention to detail comes at a price.
I'll say... ;-)
>>As I stated, I haven't done any photography with my Tak scopes for
>>a personal direct comparison. I have come across some images taken
>>through an FS-128 that seem to illustrate my points, though.
>>
>>Quentin Hinds has taken some nice shots with an FS-128 and reducer, and
>>posted them on his website. A particularly telling image is found at:
>>http://lonestar.texas.net/~wqhinds/128_434.html
>Keep in mind that his images are taken from a light polluted site.
>And I've seen the original prints. The scans were pretty bad.
>Most of the contrast was lost as were the dimmer stars. Ed Sczepanski's
>pictures are quite a bit better, but his best all come
>from west Texas. But unfortunately he has no scans of his photos.
Despite the bad scan, it sure had no problem showing the prominent large
violet haloes! My EDF shot simply has none of this. (I agree that his poor
scan may explain why my image has so much more resolution and detail).
For a very similar image to my Horsehead shot, see John Gleasons site
(Rich N. posted a reference to it, there are some excellent images there).
BIG difference between that shot and Quentin's (large violet halos).
I wonder why all of Takahashi's 'serious' astrographs are all triplets?
(FCTs)...
>But most of the photographers I know have used _both_, and picked
>the Tak for purely the photographic performance. But no one I know
>has purchased one of the new focusers (not that this means anything,
>as I think that these just started shipping this year).
We just have different experiences in this regard. You and Quentin were
the only folks I have come across that used Taks for imaging.
Nothing statistical here, but that is my experience (I know of at least
8 folks I converse with that use A-P refractors for some serious 6x7
imaging and all are quite pleased).
>Exactly. Look through the photos in the Tenmon Guide. The photos in
>S&T are garbage compared to what the Japanese are producing with
>all types of instruments. I have seen the photos that are submitted
>from non-AP refractors and are never printed and they are all quite
>a bit better. S&T just doesn't print those photos, for whatever the
>reason. Everyone keeps saying that what they should do is _say_
>that it comes from an AP refractor, just so that it would get printed,
>but no one has had the guts to actually try this.
I sure wish I could get my hands on some Tenmon Guide issues, everyone
talks highly of it.
I do find it real hard to believe that Sky&Tel selectively only prints
refractor photos taken by AstroPhysics scopes only, despite receiving
better Tak photos... Maybe from now on they will only be publishing
photos taken by Meade ETX's? :-) (a reference to some of the other
recent threads)
>The tactics, though I think do have an impact. Look how one
>person make the dramatic contrast claim, and not only did
>only one person other than me point out how idiotic that was,
>several apparently knowledgeble people leaped to his defense!
>Look how when I said that the two instruments are very similar
>in quality/performance that was viewed as "bashing"!
To be fair, I don't recall anyone making a dramatic contrast claim.
Thomas Back made what I recall was a claim of higher contrast with the
A-P design versus the Tak Doublet design (based on actual design
modelling). In relative terms, I do believe what he has said (and my
visual tests confirm the better color correction of the A-P designs over
the Tak FS and FC designs). The only thing that I could see discussion
around was to what degree the poorer color correction of the Taks detectably
affects contrast under typical conditions. The difference is there, just
how much of an effect does it have? (again, I have found it to be a small
effect with the typical seeing I have in Colorado). For persons like me
(very particular, especially when spending this kind of money), I would
prefer the better color correction and contrast of the A-P triplets, no
matter how practically small it may be for my conditions (hey, I may end
up moving back to Houston someday, or Florida).
>These tactics do have a purpose, and there is no question
>that there are certain people practicing this. The posts are
>there for all to see. There are apparently a lot of people
>that are upset that I stood up and pointed out that a certain
>Emporer had no clothes (e.g. that the Taks are very similar
>?to the APs in terms of quality and performance.)
I think the purpose was to give out some opinion and objective
information on valid points of comparison. Hopefully this has been
useful for some folks. Sounds like both Emperors, indeed, have some
nice threads.
>But by doing so I also brought out posts by you, Todd, Richard
>Whalen, et al all saying essentially the same thing. That
>the quality is almost the same (although they all saw a very
>slight edge in the planetary colour correction with the AP,
>while I saw the opposite in the two cases I tested). But all of
>these are in direct refutation to Thomas Back's claim of
>washed out contrast and others claims that the Tak is so
>horrible that under no circumstance should anyone buy one.
>I find it highly distasteful to post this to someone who doesn't
>know any better, is looking for information, and may think that
>they are telling the truth.
Who, at all, stated or even inferred that the Taks are so horrible that
they are not worth purchase? I didn't pick that up at all. I still own
a superb FS-78 (the best of all the Taks I have owned). There are no
A-P equivalents to this scope, so it remains my first choice in small
scopes (though it is essentially the same size as a Traveler 105,
it is lighter, and it is just a cool little scope).
>Well, except for that the Taks have 4" focusers, all of the numbers
>look about right. 80% actually sounds like a bit on the high side
>for the discount, so the delta-$ is actually probably a bit more. I
>agree completely that there is huge premium for the Taks and
>that visually at best one gets a barely measureable increase in
>performance. And that for this price all that one gets is immediate
>delivery and a better photographic system. So for visual work
>I have always told people that unless one is dead set on getting
>one _NOW_! the 5" and larger instruments are not recommended
>by me because one isn't getting materially better instrument.
Well, acually the ID of the FS-152 focuser that I just measured on a new
FS-152 (3 months ago) measured at 3.5" Inside Diameter, 3.75" outside
diameter. I don't have a measurement for how much the focuser tube
baffles further reduce the 3.5", but I think they were fairly thin and
didn't reduce it a lot. The A-P 4" focuser is 4" clear aperture (and
4.3" diameter where accessories attach). I expect the A-P system has
a larger fully illuminated field (but I think it is close). I don't know
what the Tak flatteners or reducers do (whether they reduce the fully
illuminated field size or not). At any rate, the Pentax 67 body vignettes
on its own at the corners and edges...
The FS-128 scope I owned had a fully illuminated field of only 0.5" max., due
to the restrictive baffling, while an FS-102 had a larger field (more like
1"). My FS-78 is tiny, with only an .25" field. None of these scopes
would have a large enough fully illum. field to work well for medium
format (35mm would be fine). I have no idea why Tak chose to incorrectly
baffle these scopes this way (too restrictive, adds nothing to stray light
control if baffles are properly sized and spaced).
Do you notice much vignetting on your medium format images through the
smaller (under 2.7") Tak focusers?
Anyways, I have probably started repeating myself on some of my points, so
I will throttle back for now. Plus, new moon is approaching and it is
time to get back to viewing and imaging.
Thanks for the info. on the BRC-250. Hopefully it will be a superior
alternative someday to the 6" refractors. Still, it is hard to beat the
robustness, simplicity, and performance of refractors for large
formats.
Bob Luffel
Jason Adamik
Nagler used (through Astromart, so I didn't examine the ep first), and
it had minor but noticeable cosmetic differences compared to my
Japan-made Naglers: the chrome plating wasn't perfect on the barrel, the
end of the barrel didn't have the flat/machined look I'm used to
(rounded a bit, not perfect...), the flat-black painted parts inside the
barrel were not perfectly covered (some brass showing), and the coating
on the field lens didn't look perfect. Also, the lettering 'Taiwan' was
the cheaper thermographic type instead of the engraving I was used to.
--Jason
Jason Adamik
Jason Adamik
Jason Adamik
Jerry Lodriguss
> the larger blue star images. I see this on virtually every shot of
> the horsehead, even those from reflectors. Perhaps the cause is
> some other scattering effect in the film or instrument (not halation,
> per se?). Those are very bright stars, a real acid test.
>
> I assume that PPF has an anti-halation layer, but why would it only
> show up on the red layer? Any film experts out there?
I'm no expert, but I'll add some small info here. The red layer is
bottom one, next to the film base, so it suffers more from halation. But
the film type and its sensitivity to red stars seems to play a big role
too.
I have an example of the same object shot on the same night, same scope,
but different films that show very different red halos. Take a look at:
http://astrosurf.com/neptune/astropix/HTML/I_ASTROP/REDHALOS.HTM
I see some blue halos too around bright stars near the Horsehead, see:
http://astrosurf.com/neptune/astropix/HTML/B_WINTER/B33.HTM
Could this come from strong ultra-violet in the stars that is not well
corrected in the scopes but is not visible to the eye, but is visible to
the film? I know most of these films have some sensitivity down around
400nm. Is that visible to the eye? How well corrected is that
wavelength in these scopes?
Jerry
Paul Gustafson
variation from 405nm to 706nm."
Paul Gustafson
Jerry Lodriguss <j...@nospammers.astropix.com> wrote
snip
Blandp1
I find none of the things you mention. I'm comparing them to an old Japan 32mm
Widefield (newer style with rubber grip ring) - the chrome is perfect, the
lettering just as engraved, the end of the barrel flat, the black coatings just
as good, the coatings just as good.
-Philip J. Blanda III
In article <370D6C2D...@home.com>, Jason Adamik <ada...@home.com> writes:
>Japan-made Naglers: the chrome plating wasn't perfect on the barrel, the
>end of the barrel didn't have the flat/machined look I'm used to
>(rounded a bit, not perfect...), the flat-black painted parts inside the
>barrel were not perfectly covered (some brass showing), and the coating
>on the field lens didn't look perfect. Also, the lettering 'Taiwan' was
>the cheaper thermographic type instead of the engraving I was used to.
PGP Public key available
tomd...@my-dejanews.com
Stard...@webtv.net wrote:
> I know this is kind of off topic BUT since you guys are discussing high
> end optics, I'd like your opinions. How do the images in Mak-Newts
> compare to APOs? I have a hard time taking magazine reviews at face
> value, but the Mak-Newt design seems promising. Also, would an AP900
> mount be able to carry a 10" or 12" Mak-Newt if such a scope exists?
> Would the FOV in a f/6 Mak-Newt be the same as an f/6 APO?
> Thanks for any opinions. Clear Skies!
>
> Stard...@webtv.net (David M)
I recently asked ITE about the 10" Mak-Newt (MN 106), and its weight is
50-60 lbs depending on tube type, so a 900 could support it.
Tom DeMary
tomd...@my-dejanews.com
Lumpy Darkness
: Re: the Taiwan vs. Japan-mfg'd TVue ep's: I bought one Taiwan-made
: Nagler used (through Astromart, so I didn't examine the ep first), and
: it had minor but noticeable cosmetic differences compared to my
I can only say that buying used, sight unseen, has risks. Who knows the
history of your particular eyepiece.... you certainly don't. That is why
I prefer to buy new, or from friends, locally (I never have and do not
plan to buy on Astromart).
Question.... before you posted your remarks, did you telephone Tele Vue to
discuss the eyepiece with them? They have a wonderful reputation for
outstanding customer service....
--
-Lumpy Darkness-
Northern California amateur astronomers, check out TAC
The Astronomy Connection at http://www.seds.org/TAC
lude...@my-dejanews.com
Stard...@webtv.net wrote:
> I know this is kind of off topic BUT since you guys are discussing high
> end optics, I'd like your opinions. How do the images in Mak-Newts
> compare to APOs? I have a hard time taking magazine reviews at face
> value, but the Mak-Newt design seems promising. Also, would an AP900
> mount be able to carry a 10" or 12" Mak-Newt if such a scope exists?
If you would buy the factory made 10" , it would work well with the AP 900, if
you would buy the factory made 12" , it would be to heavy and to long for the
AP 900. if you buy buy an custommade 12" (F/6.3) with lightweight tube ( as my
friend Allen Chan have under order) it would work well with the AP 900 too.
> Would the FOV in a f/6 Mak-Newt be the same as an f/6 APO?
yes, will an little vigneting on the edge, but mostly not visible.
best wishes
Markus
> Thanks for any opinions. Clear Skies!
>
> Stard...@webtv.net (David M)
> I love the night.The day is okay and the sun can be fun but I love to
> see those rays slip away--Blue Oyster Cult
>
>
-----------== Posted via Deja News, The Discussion Network ==----------
Del Johnson
sharper than the 35mm Panoptic. The 35mm may be distorted due to the larger
exit pupil, but I don't seem to see the effect with my 55mm Plossl.
Del Johnson
Jason Adamik
so I did not call them. I have experienced their customer service, and
it is good, as you said. I simply offered the notes on my Taiwan-made
eyepiece in response to the original post in this thread. I like really
perfect eyepieces, so that is the only reason I bothered selling it and
buying an equivalent 'Japan' unit. Most people wouldn't notice or care
about the tiny differences I found, IMO.
--Jason
HC
>
> Re: the Taiwan vs. Japan-mfg'd TVue ep's: I bought one Taiwan-made
> Nagler used (through Astromart, so I didn't examine the ep first), and
> it had minor but noticeable cosmetic differences compared to my
> end of the barrel didn't have the flat/machined look I'm used to
> (rounded a bit, not perfect...), the flat-black painted parts inside the
> barrel were not perfectly covered (some brass showing), and the coating
> on the field lens didn't look perfect. Also, the lettering 'Taiwan' was
> the cheaper thermographic type instead of the engraving I was used to.
>
My Taiwan-made 19mm Panoptic is my favorite eyepiece because it's
optically and mechanically just as perfect as my Japan-made 7mm Nagler.
I haven't personally compared a new Taiwan-made 7mm Nagler to a new
Japan-made 7mm Nagler, which explains why I sent my question to the
"Ask Al" forum. It turns out Al's answer revealed something even
more interesting about a certain TeleVue's competitor's ultra-wide
angle eyepieces. From Al's reply, I also found out that he does
indeed read this newsgroup, but he just refrains from posting
anything here to avoid getting into endless battles, which again
proves how smart he is.
Eric Faust
of the location they were manufactured. All of my TV eyepieces are made in
Taiwan, including the 13mm Nagler. There are some differences. For instance,
the 13mm nagler has a thickly chromed brass 1.25" barrel and a machined
aluminum 2" barrel. On the 22mm Panoptic, both the 1.25 and 2" barrels appear
to be machined from a single piece of stock. All of the machining, engraving,
etc, is perfect. Discussing the pro's and con's of the 2 locations or even of
each change is great, but do you really feel his answer was misleading or
"questionable"? I do not, however, it is wise to take any comments made from a
manufacturer about his product line with a grain of salt.
Eric
In article <370E2384...@home.com>, ada...@home.com says...
HC
>
> -snip-
>
> >Reminds me of another "guru" complaint, that some Panoptics are sharper
> >than others. More nonsense.
>
> first impulse is to question the accuracy of the quote.
>
> -snip-
>
So you don't agree with Al's statement below?
RichardN22
chose to keep it. As I've said over and over, it is not a *bad* EP.
But it is the weakest of the Panopt line, and the one model where
there is at least one competitor who produces a unit with both a
better image and a cheaper price. >>
In your opinion that eyepiece would be??
Richard
Richard Navarrete
Richa...@aol.com
Astrophotography Web Page - http://members.aol.com/richardn22
HC
>
> No, I don't.
>
> Please reread the post. Both _longer_ and _shorter_ FL EPs were
> sharper. This was tried on multiple OTA of quite varied design,
> aperture, FL, and f/ratio. And this was with multiple observers.
>
> -snip-
Well, let's not compare different eyepiece designs.
TeleVue doesn't have a Panoptic EP with FL>35mm.
Al was talking about different focal lengths of the same design.
He was not comparing the sharpness of the 35mm Panoptic to the
50mm Takahashi. A more appropriate question would be: do you notice
any difference in sharpness between 50mm Tak and the 18mm Tak?
Er451
been printed recently that were taken with TV and Borg refractors. There does
not appear to be a bias towards photographs from one telescope manufacturer or
another, as in any given issue it is usually
a mix of photographs taken with SCT's, reflectors, and refractors, whether it
be from Celestron, Meade, or whomever. I have sent them my photographs taken
through AP refractors before, and although they printed one, most they didn't,
because the quality of the my photo's did not meet their standards.
In regards to Tom Back, I have found him to be very knowledgeable about
astronomy and optics and honest in his evaluation of telescope equipment. If he
tests a telescope, and notices good or bad points about it, he reports his
findings truthfully, whether it is from AP, Tak, TV, or any other manufacturer.
If he seems to like AP refractors it's because through his tests and
observations with them he feels they are of excellent
quality (as do I). I feel his knowledge and experience is an asset to this
hobby.
Eric Jamison
Allan Rahill
There is a difference between Japan and Taiwan Nagler eyepieces.
About a year ago I bought a second hand 9mm Nagler via astromart to match
my old 9mm NAgler (no rubber eyecup) to be used with the binoviewer. The
one I received was the newest model. When combined in the binoviewer (yes
we can see easely both eyes with these large eyepeices)... I was surprised
to see the image brighter in one of my eyes. At first I thought it was
my eye or the binoviewer the problem. Than I switched the eyepeices
left-right on the binoviewer. I looked again and found the image was
brighter in the other eye. I blinked my eyes to see significant
differences in brightness. I have the impression the coatings in the old
Japan Nagler eyepeices were more effective than the new taiwan eyepeices.
Contrast was also a bit better for the Japan eyepeice in this test!
> HC wrote:
> >
> > I posed this question to "Ask Al", and he somehow made a big mistake
> > when rephrasing my original question. Here is the e-mail that I sent
> > directly to the "Ask Al" forum:
> >
> > Someone has commented on sci.astro.amateur that the new
> > "Made In Taiwan" Nagler 7mm eyepieces are optically not
> > as good as the old "Made In Japan" ones. Assuming the
> > design and manufacturing specs of the Nagler 7mm have
> > not changed, how can that be true?
> >
> > And here is Al Nagler's response in its entirety:
> >
> > Nonsense. Some people blithely confuse the manufactured origin of
> > eyepieces and seem to delight in rewriting history to match a personal
> > agenda.
>
>
~~~~~~
Allan Rahill ( )
~~/ -- )
(____ CMC )
Canadian Meteorological Center, Dorval, Canada (_______)
////
'''
Jason Adamik
a 'camera' at the stated f/ratio of f/4). Beautiful star images across
the very wide field. I started asking questions about Borgs after that.
--Jason
Jason Adamik
--Jason
Robert
I thought you know a little about scopes.
Astro-Physics doesn't make eyepieces. They did collaborate with Zeiss/Baader and
brought the famous orthos to the US. I have 9 of them, and I'm hoping to find 6
more to complete an in depth side by side comparison to the Pentax orthos.
I like the ease of modularity of the Binoviewer, BarCon, and the Maxbright. While
it's true these accessories will work with any 2" focuser, it's clear when they're
all together, the were designed to work as a team. The sturdy 2.7" and 4"
focusers on the AP's make a BarCon, Maxbright, Binoviewer, and heavy eyepiece
combination a breeze to use, with no image shift on focusing, or changing objects.
I had assumed you had seen, or used some of this equipment based on many of your
posts. I assumed you would understand the ease of use of the AP accessories.
Have you ever used a:
BarCon?
Maxbright?
Zeiss Binoviewer?
AP 155 mm?
AP 130 mm?
AP 105 mm?
How did you find the ease of use of the listed accessories?
You have such strong opinions on scopes, I'm curious to see how your impressions
compare to mine.
Thanks,
Rob
RAnder3127 wrote:
Sue and Alan
You seem to be ignoring the fact that there are three optical systems in use
by an observer - the eyepiece, the telescope, and the eye. If you are
comparing the 35mm Pan to the 22mm Pan you will have a larger exit pupil
with the 35mm. When an exit pupil gets as large as 6mm you really start to
see the defects of your eye. If you are comparing the eyepieces on one
telescope you are always going to have a larger exit pupil with the 35mm
Pan.
You also have to be careful compaing eyepieces on different scopes. The
scope design/eyepiece combination makes a difference. The f/ratio makes a
difference. The only fair way to compare a 35mm Pan to a 22mm Pan would be
to find two telescopes of the same design and same f/ratio that would yield
identical magnifications (and, hence, exit pupils). And you want an exit
pupil small enough to eliminate your eye from the equation.
Texereau has an interesting discussion on this (page 216, How to Make a
Telescope, second edition). It includes the following -
"Finally, in this case also (f/6 beam and 6-millimeter pupil), we find that
to speak of image quality at the edge of the field is, in a sense,
meaningless; the defects of the eye enter here in a variable, almost
unpredictable way. For best viewing the pupil of the eye normally adjusts
itself the coincide with the exit pupil. But in turning to an object at the
edge of the field, the eye rotates about a center positioned a considerable
distance behind the pupil. Effectively, therefore, the pupil is diaphragmed
down like a cat's eye, and vision is no longer centered near the axis of the
cornea, where alone the eye has sufficient optical quality."
Clear skies, Alan
ddd wrote in message <37106659....@news.texas.net>...
[SNIP]
>
>Mr. Nagler overall makes the best EPs. But when it comes to the
>Panoptic line when he says that there is zero difference in the image
>between the different models he is dead wrong.
Todd Gross
>No, I don't.
>
>Please reread the post. Both _longer_ and _shorter_ FL EPs were
>sharper. This was tried on multiple OTA of quite varied design,
>aperture, FL, and f/ratio. And this was with multiple observers.
>
>Plus someone else just post the exact same experience.
>
>Mr. Nagler overall makes the best EPs. But when it comes to the
>Panoptic line when he says that there is zero difference in the image
>between the different models he is dead wrong.
>
With all due respect Gene, I think that the Nagler's opinion should be
considered here. They have told me numerous times in email and in
person that the eyepiece lines are consistent in optical performance.
I would suggest calling them and finding out more about this and
reporting back, because I have come to find that various scopes
act different ways (there are a host of variables) with different eyepieces..
and other aberrations get thrown in. There is something to this, and instead
of just reporting the optical results as you see them, finding out the
theoretical would be beneficial too so we can all find the source of
variation, rather thanjust assuming it's the eyepiece.
Sue and Alan
22mm Pans on scopes with the same f/ratio. The exit pupil with the 35mm Pan
is going to be 60 percent larger (by diameter). So you'd have to settle for
a situation where the exit pupil on the 35mm Pan would be small enough to
pretty much eliminate eye defects from the equation.
Clear skies, Alan
Sue and Alan wrote in message <7enl4f$2v...@news1.newsguy.com>...
>[SNIP]The only fair way to compare a 35mm Pan to a 22mm Pan would be
RAnder3127
>Have you ever used a:
>
>BarCon?
No. Never heard of it.
>Maxbright?
Yes, most AP refractors have these.
>Zeiss Binoviewer?
Not a Zeiss.
>AP 155 mm?
Yes. A couple.
>AP 130 mm?
Yes. Many.
>AP 105 mm?
Yes. Many.
Your forgot Roland's 7.1" which I was fortunate to at least
look through for awhile.
-Rich
Death to Divx; Long Live DVD!
"If Tandy (Radio Shack) or Blockbuster
(who censor videos) adopt Divx, please
boycott them. Divx is Evil incarnate."
RAnder3127
>Rich,
>
>I thought you know a little about scopes.
>
>Astro-Physics doesn't make eyepieces. They did collaborate with Zeiss/Baader
>and brought the famous orthos to the US.
Yes, we've all heard Zeiss produced 400 sets, 300 for Baader,
100 came to the U.S and could be bought from AP and C7.
But AP neither designed, built or assembled the eyepieces.
Forgive me, I also buy audio equipment and when people start
talking about buying from one manufacture entire systems,
I cringe. That is what sells $1000 rack systems in Circuit City.
RAnder3127
writes:
>To be fair to S&T, they do print photo's from non-AP refractors. Several have
>been printed recently that were taken with TV and Borg refractors. There does
>not appear to be a bias towards photographs from one telescope manufacturer
>or
>another
No one said there was. But, if many U.S. astrophotographers are
using AP scopes, the of course you will have a large number of
the pictures being made with AP's. If it were Taks, then you'd see
more pictures taken with Taks. Years ago, it was SCT's.
In a way, it's a pity because the relative image-scale of the
pictures in the mags seems to have gone down so now we
see more widefield shots than close-ups of deepsky objects.
Some of this is due to the shorter f.l.s of refractors and the
fact they support large format film.