Best eyepiece design for planetary oberserving
Michael E. Rohde
ability to maximize surface details is a top priority.
Thanks,
Mike
TMBack
>observing. The ability to maximize surface details is a
>top priority.
The triplet cemented Steinheil Monocentric, with
the two outer surfaces multicoated with either the Zeiss
T-coat, or the Pentax SMC multicoat.
Thomas Back
TMB Optical
William H. Foley, Sr.
> What is the best overall eyepiece design for planetary observing. The
> ability to maximize surface details is a top priority.
>
> Thanks,
> Mike
It is probably Hastings Triplet. Lots of luck finding one, you may have
to get a magnifier from Edmund or some other optical source, and make a
proper-sized
mount for it to go in your focusser. Other good choices exist, but
depend on the
type and f-value of your scope.
Bill.
Alan French
I see you are getting suggestions for eyepieces that are almost impossible
to find. IMHO, that is not very helpful. Although you did ask for the best
overall eyepiece design, it would be nice if it was one you could easily
buy.
The relatively inexpensive UO Orthos get good marks for planetary viewing.
I think the Orthos sold by Pocono Mountain Optics are the same eyepiece for
a bit less money. I know the older Edmund Orthos we have were made by Taney
(sp?), which is the company that makes the UO Orthos.
Unless you are already an avid and demanding planetary observer you would
probably be quite happy with the TeleVue Plossls or any of the similar
eyepieces available. Once you get some idea of what powers your scope and
location support then you can start thinking about getting the best possible
planetary eyepiece in appropriate focal lengths.
Clear skies, Alan
"Michael E. Rohde" <mro...@infinet.com> wrote in message
news:3a05951a$0$35389$2a0e...@news.tdin.com...
TMBack
>I see you are getting suggestions for eyepieces that are
>almost impossible to find.
Don't be too sure of that Alan. :-)
>IMHO, that is not very helpful. Although you did ask for
>the best overall eyepiece design
Yes, that is exactly what he asked, not what is the
best current available or best value planetary eyepiece.
Thomas Back
TMB Optical
Bill Becker
Just curious...would you say that Nikon 5mm ortho of yours is the best
planetary ocular you have personally ever used? The "best" I've ever
used is the 5mm Pentax ortho, when local conditions allow.
Best regards,
Bill
TMBack
>Just curious...would you say that Nikon 5mm ortho of
>yours is the best planetary ocular you have personally
>ever used? The "best" I've ever used is the 5mm Pentax
>ortho, when local conditions allow.
The 5mm Pentax ortho is close, but the Nikon 5mm
ortho is the best 5mm planetary eyepiece on the planet.
From my observer notebook: (My drawing was sent to
the B.A.A. Mars section).
Mars
2-18-95
C.M. 170
AP 180mm f/9 EDT
324x (Nikon 5mm)
Antoniadi scale I
Moments of perfect seeing! Nix Olympica
clearly visible. The deserts appeared mottled
at the best moments. The best view of Mars
that I've ever had....
Thomas
Mike McIsaac
> >What is the best overall eyepiece design for planetary
> >observing. The ability to maximize surface details is a
> >top priority.
>
> the two outer surfaces multicoated with either the Zeiss
> T-coat, or the Pentax SMC multicoat.
>
> Thomas Back
> TMB Optical
>
And where might dedicated planetary observers such as myself and Mr.
Becker acquire such an eyepiece? Until then, we'll have to "settle" for
our Pentax SMC orthos...
Clear skies!
Mike McIsaac
60*N 150*W
--
*********************************************
186,000 miles per second: its not just a good
idea, its the law!
*********************************************
Sent via Deja.com http://www.deja.com/
Before you buy.
Larry Brown
Where would one find Pentax and Nikon orthoscopics? Does anyone know
of a dealer in the U.S. for these eyepieces. I would also like to know
where the monocentric eyepieces could be obtained. Edmund sells a
hastings triplet in three focal lengths (8, 12.5, 25 I think) for $50.00
each, but they would need to be mounted in something. I'm tempted to do
this. They also sell Steinheil triplets, but they are longer focal
lengths. Any info would be greatly appreciated. I have a twenty-year old
set of Meade orthoscopics, and they are currently my favorites.
Thanks. L. Brown
Alan French
So, should I be saving my nickels and dimes <g>?
Clear skies, Alan
"TMBack" <tmb...@aol.com> wrote in message
news:20001105160912...@ng-mg1.aol.com...
> Alan wrote:
>
> >I see you are getting suggestions for eyepieces that are
> >almost impossible to find.
>
> Don't be too sure of that Alan. :-)
> [SNIP]
Bill Becker
You can still get, from time to time, some of the Pentax orthos through
Markus at:
http://www.apm-telescopes.com
He currently is advertising the 7mm. Another good source is the
Astromart classifieds. Hey, it worked for me. ;^)
I tried an ad for some Nikon orthos but, not surprisingly, no one wanted
to part with one. Good luck.
Best regards,
Bill
William H. Foley, Sr.
> Mike,
>
> I see you are getting suggestions for eyepieces that are almost impossible
> to find. IMHO, that is not very helpful. Although you did ask for the best
> overall eyepiece design, it would be nice if it was one you could easily
> buy.
>
> The relatively inexpensive UO Orthos get good marks for planetary viewing.
> I think the Orthos sold by Pocono Mountain Optics are the same eyepiece for
> a bit less money. I know the older Edmund Orthos we have were made by Taney
> (sp?), which is the company that makes the UO Orthos.
>
> Unless you are already an avid and demanding planetary observer you would
> probably be quite happy with the TeleVue Plossls or any of the similar
> eyepieces available. Once you get some idea of what powers your scope and
> location support then you can start thinking about getting the best possible
> planetary eyepiece in appropriate focal lengths.
>
> Clear skies, Alan
>
> "Michael E. Rohde" <mro...@infinet.com> wrote in message
> news:3a05951a$0$35389$2a0e...@news.tdin.com...
> > What is the best overall eyepiece design for planetary observing. The
> > ability to maximize surface details is a top priority.
Hi again from Bill.
Again, the triplets are the best for planetary observing over a range of
different designs and F/values of telescopes. Yes, some orthos and Plossls
would be OK but you have not let us know the scope you plan to use. For
instance, if you are using a long-focus refractor, then a Ramsden would be a
good choice, but if you are using a Coulter Odyssey, it would be a terrible
choice.
What you want is a very high quality eyepiece, with a very short focal length,
but not too short for the diameter and focal length of your telescope. This
would probably narrow the choice down to University Optics 4mm or 5mm Orthos,
Televues with a similar EFL. or perhaps at http://www.apogeeinc.com/ you might
want to look at the Super Easy-View Eyepieces at $119.95 each. With a REALLY
good Barlow, like a Klee or other 3-element type, you might even be able to push
the magnification higher. However, depending on the aperture, quality, and
design of your scope, there is a limit to magnification beyond which the image
will begin to deteriorate. Look on the Web for optical formulas, especially
those to do with astronomy.
I think there may be some discussions of limits there.
Best Wishes,
Bill.
William H. Foley, Sr.
> Alan wrote:
>
> >I see you are getting suggestions for eyepieces that are
> >almost impossible to find.
>
> Don't be too sure of that Alan. :-)
>
> >IMHO, that is not very helpful. Although you did ask for
> >the best overall eyepiece design
>
> Yes, that is exactly what he asked, not what is the
> best current available or best value planetary eyepiece.
>
> Thomas Back
> TMB Optical
You folks following this thread: I do hope you know WHO TMBack is. Try
thinking TMB refractors. I, for one, am going to pay attention here!
Bill.
Modmed3
Hi Tom -
That certainly sounds like a magical night. Just out of curiosity, did you
observe through the Nikon exclusively, or did you compare other orthos (Pentax,
UO, Tak, et al.) during that particular session?
Regards,
Ed Todd
(currently on the ultimate dream planetary ep quest)
Vahe Sahakian
> ability to maximize surface details is a top priority.
Along with recommendations by other posters for non existent eyepieces
here is my recommendation:
My best planetary eyepiece is 25mm Zeiss ortho, this of course requires
a scope with very long focal length but that is what I have.
Very comfortable eye relief, if that matters to you, and an exceptional
contrast, it is amazing how dark a sky can be seen with this eyepiece
right next to Jupiter's limb.
Thanks,
Vahe
Vahe Sahakian
>
> What is the best overall eyepiece design for planetary observing. The
> ability to maximize surface details is a top priority.
Just curious, what kind of scope do you have? The ability to Maximize
surface details really starts with state of art telescope optics and if
you do not have one you will see very little difference between Zeiss
Orthos and a Vixen Lanthanum.
Thanks,
Vahe
hg...@my-deja.com
tmb...@aol.com (TMBack) wrote:
> Bill,
>
> >Just curious...would you say that Nikon 5mm ortho of
> >yours is the best planetary ocular you have personally
> >ever used? The "best" I've ever used is the 5mm Pentax
> >ortho, when local conditions allow.
>
> The 5mm Pentax ortho is close, but the Nikon 5mm
> ortho is the best 5mm planetary eyepiece on the planet.
> From my observer notebook: (My drawing was sent to
> the B.A.A. Mars section).
>
> Mars
> 2-18-95
> C.M. 170
> AP 180mm f/9 EDT
> 324x (Nikon 5mm)
>
> Antoniadi scale I
>
> Moments of perfect seeing! Nix Olympica
> clearly visible. The deserts appeared mottled
> at the best moments. The best view of Mars
> that I've ever had....
>
> Thomas
Howdy, Thomas. Just curious, what's your opinion of the Takahashi
orthos?
David Neal Minnick
Lake Elsinore, CA
lude...@my-deja.com
you talking about the newer 1.25" or the older 0.965" ? If you talking
about the older 0.965", than I like to left an message here, that I
came across with 6 pc of such 25 mm zeiss eyepieces 0.965" in new
condition and they are available from stock .
Also maybe its now time to open an secret, about which nobody knows:
We could force Pentax to start an new Run of the SMC orthos, this time
they will be made with 1.25" Barrel. This run will be an exclusiv
production for the european Pentax Importer. They should become
available sometimes next year. Keep your eyes open on my ads
best wishes
Markus
> Along with recommendations by other posters for non existent eyepieces
> here is my recommendation:
> My best planetary eyepiece is 25mm Zeiss ortho, this of course
requires
> a scope with very long focal length but that is what I have.
> Very comfortable eye relief, if that matters to you, and an
exceptional
> contrast, it is amazing how dark a sky can be seen with this eyepiece
> right next to Jupiter's limb.
>
> Thanks,
> Vahe
>
lude...@my-deja.com
www.apm-telescopes.com
lu...@ur.pils.de
Markus
TangoDe...@fuse.net wrote:
>
> Where would one find Pentax and Nikon orthoscopics? Does anyone
know
> of a dealer in the U.S. for these eyepieces. I would also like to know
> where the monocentric eyepieces could be obtained. Edmund sells a
> hastings triplet in three focal lengths (8, 12.5, 25 I think) for
$50.00
> each, but they would need to be mounted in something. I'm tempted to
do
> this. They also sell Steinheil triplets, but they are longer focal
> lengths. Any info would be greatly appreciated. I have a twenty-year
old
> set of Meade orthoscopics, and they are currently my favorites.
>
> Thanks. L. Brown
>
>
Toddwx
TMBack
>That certainly sounds like a magical night. Just out of
>curiosity, did you observe through the Nikon
>exclusively, or did you compare other orthos
>(Pentax, UO, Tak, et al.) during that particular session?
It was! I also used a 3.8mm XP and 6mm Pentax
SMC that night. I had since tested the 5mm Pentax vs.
the 5mm Nikon and sold the 5mm Pentax. The 5mm
Nikon gave the best image and contrast of the three
eyepieces on that night. The 3.8mm XP gave a very fine
image, but the subtle mottling was best seen in the 5mm
Nikon. The 6mm Pentax gave a razor sharp view, but it
wasn't quite enough power.
Thomas
TMBack
>Just curious, what's your opinion of the Takahashi
>orthos?
I rate them very highly, among the best planetary
eyepieces. The only superior planetary eyepieces
I've found are the 1.25" Zeiss Abbe's, plus the
Nikon and Pentax orthos.
Thomas
TMBack
>So, should I be saving my nickels and dimes <g>?
All I can say at this point is that's a good possibility.
Thomas
TMBack
>And where might dedicated planetary observers such as
>myself and Mr. Becker acquire such an eyepiece? Until
>then, we'll have to "settle" for our Pentax SMC orthos...
"Settle" for our Pentax SMC orthos? That's a good
place to settle! You can build the monocentrics from
about 4 different suppliers of the triplet element, or
maybe wait, and a new product will be on the market.
:-)
Thomas
TMBack
>the 2.8mm hi-ortho.. your opinion?
The best ultra high power planetary eyepiece.
Thomas
Chris1011
maybe wait, and a new product will be on the market.
:-)>>
Sounds like a good eyepiece is coming for long Maks and experienced observers
who don't mind small fields.
Roland Christen
William H. Foley, Sr.
> Hi Mike,
>
> >And where might dedicated planetary observers such as
> >myself and Mr. Becker acquire such an eyepiece? Until
> >then, we'll have to "settle" for our Pentax SMC orthos...
>
> "Settle" for our Pentax SMC orthos? That's a good
> place to settle! You can build the monocentrics from
> about 4 different suppliers of the triplet element, or
> maybe wait, and a new product will be on the market.
> :-)
>
> Thomas
Just a word here from old Bill: I stated that the Hastings Triplet
would be a great planetary eyepiece. That was incorrect, my (grossly)
imperfect memory was mixed up on this one - the one-time great planetary
eyepieces were the monocentric (as Tom stated) and the Tolles. However,
if you are used to Naglers, Koenigs, and the like, looking into one of
these just MIGHT give you claustrophobia. Think of 15-20 degrees
instead of 50-84 and you might get the idea. However, if you are REALLY
intent on seeing fine detail on a planetary surface, you might find that
there is less distraction in the very small FOV than in a large one, and
you can concentrate better on what you WANT to see. But, again, you are
warned about a SERIOUS change in FOV.
P.S. - Unless you have a very long F.L. telescope, a Hastings 8mm would
probably not give you sufficient magnification. I believe you would
need a 2400 mm or longer objective to really get Mars close in, for
instance. And a Hastings is NOT a monocentric.
Bill.
Vahe Sahakian
> about the older 0.965", than I like to left an message here, that I
> came across with 6 pc of such 25 mm zeiss eyepieces 0.965" in new
> condition and they are available from stock .
>
> Also maybe its now time to open an secret, about which nobody knows:
>
> We could force Pentax to start an new Run of the SMC orthos, this time
> they will be made with 1.25" Barrel. This run will be an exclusiv
> production for the european Pentax Importer. They should become
> available sometimes next year. Keep your eyes open on my ads
Markus,
I use a pair of 1.25" Zeiss in Zeiss binoviewer, this eyepiece
combination gives 275x without barlow with my 10" MCT, based on very
limited experience this is about the optimum power for viewing Jupiter,
the quality of the image is simply amazing with this eyepiece.
Thanks,
Vahe
Larry Brown
I have been looking for such an eyepiece. Why a Steinheil and not a
Hastings?
Patrick and Penny Kelly
The 5mm Pentax ortho is the only one I'm missing and, lacking finding
one, where can I find out more about the Nikons as a possible substitute
to use with my FS102? Any net-dealers carry them? Got my SMC orthos from
Markus Ludes.
Steady skies and many thanks
Patrick in Baltimore
William H. Foley, Sr.
> I have been looking for such an eyepiece. Why a Steinheil and not a
> Hastings?
I believe that the Monocentric is corrected for more aberrations than
the Hastings. The Hastings is a simple DCX 3-element cemented
achromat. The Monocentric is more complex and should allow a larger
accurate FOV.
Just IMHO.
Bill.
William H. Foley, Sr.
Back to the original question, though - I looked at the Edmund Industrial
Optics site, and the Hastings they have looks more like it would work as
an eyepiece than the Steinheil they have. It does have both chromatic
and spherical correction, and is supposed to minimize barrel/pincushion
distortion. The Monocentric Triplet as shown in Sidgwick's Amateur
Astronomer's Handbook does not look like either the Hastings or the
Steinheil. Tom Back seemed to be hinting at an announcement of some
high-performance planetary eyepiece, let's see what he comes up with. In
the meantime, if you could find an inexpensive Hastings (I think that
almost $50 is a bit high), it might be worth testing in a jerry-rigged
holder. In the meantime, it looks like Orthoscopics are the best
currently available eyepiece for planetary use.
Bill.
Bill Becker
Markus currently has some of the Nikons on his second hand page:
http://www.apm-telescopes.com
I've also read that, thanks to Markus' efforts, Pentax will be making
more orthos and they will be in the 1 1/4" format. Hope this helps.
Best regards,
Bill
Patrick and Penny Kelly
news regarding the possible European run of Pentax orthos. I'll keep an
eye out on this.
Patrick in Baltimore
Larry Brown
> Back to the original question, though - I looked at the Edmund Industrial
> Optics site, and the Hastings they have looks more like it would work as
> an eyepiece than the Steinheil they have. It does have both chromatic
> and spherical correction, and is supposed to minimize barrel/pincushion
> distortion.
Thanks for the info. I can machine a plastic cap to hold the lens and a
field stop. I have some brass eyepiece barrels (from Apogee) to finish it
up. I think I'll go ahead and make a 12mm triplet and try it on my
refractor. The Edmund Hastings is 8mm in diameter, which makes it f/1.5 or
so. Should work. Thanks again.
Vahe Sahakian
> > the Hastings. The Hastings is a simple DCX 3-element cemented
> > achromat. The Monocentric is more complex and should allow a larger
> > accurate FOV.
> >
> > Just IMHO.
> >
> > Bill.
>
> Optics site, and the Hastings they have looks more like it would work as
> an eyepiece than the Steinheil they have. It does have both chromatic
> and spherical correction, and is supposed to minimize barrel/pincushion
> Astronomer's Handbook does not look like either the Hastings or the
> Steinheil. Tom Back seemed to be hinting at an announcement of some
> high-performance planetary eyepiece, let's see what he comes up with. In
> the meantime, if you could find an inexpensive Hastings (I think that
> almost $50 is a bit high), it might be worth testing in a jerry-rigged
> holder. In the meantime, it looks like Orthoscopics are the best
> currently available eyepiece for planetary use.
This is an interesting thread and I hope that I can learn something from
all of this since planets are my prime interest.
I am still left with one question regarding planetary eyepieces, one
important item that has not been touched on so far is the high quality
of polish and coatings, this is what makes Zeiss, Pentax and Tak orthos
so special and I am not certain if one can ever find that level of
quality in polish and coatings in a Monocentric Triplet or a similar
inexpensive offerings from Edmund or other sources.
Thanks,
Vahe
Bill Becker
Thanks for the feedback. I still have my observing notebook from when I
started in Dec 1966 and love to refer to it from time to time. I noted
being very disappointed with my first view(Dec 12, 1966) of Saturn's
rings in my 3" reflector.....;^)
Best regards,
Bill
Mike McIsaac
> This is an interesting thread and I hope that I can learn something
from
> all of this since planets are my prime interest.
> I am still left with one question regarding planetary eyepieces, one
> important item that has not been touched on so far is the high quality
> of polish and coatings, this is what makes Zeiss, Pentax and Tak
orthos
> so special and I am not certain if one can ever find that level of
> quality in polish and coatings in a Monocentric Triplet or a similar
> inexpensive offerings from Edmund or other sources.
>
> Thanks,
> Vahe
>
marketing "new, improved Zeiss Super T* Multicoating in a Can" or
something.
Mike McIsaac
60*N 150*W
--
*********************************************
186,000 miles per second: its not just a good
idea, its the law!
*********************************************
Jerry
Griot in a custom machined brass barrel. It turned out very nice,
however scratch & dig surface quality is not very good on this
particular lens.
William H. Foley, Sr.
> > > I believe that the Monocentric is corrected for more aberrations than
> > > the Hastings. The Hastings is a simple DCX 3-element cemented
> > > achromat. The Monocentric is more complex and should allow a larger
> > > accurate FOV.
> > >
> > > Just IMHO.
> > >
> > > Bill.
> >
> > Back to the original question, though - I looked at the Edmund Industrial
> > Optics site, and the Hastings they have looks more like it would work as
> > an eyepiece than the Steinheil they have. It does have both chromatic
> > and spherical correction, and is supposed to minimize barrel/pincushion
> > distortion. The Monocentric Triplet as shown in Sidgwick's Amateur
> > Astronomer's Handbook does not look like either the Hastings or the
> > Steinheil. Tom Back seemed to be hinting at an announcement of some
> > high-performance planetary eyepiece, let's see what he comes up with. In
> > the meantime, if you could find an inexpensive Hastings (I think that
> > almost $50 is a bit high), it might be worth testing in a jerry-rigged
> > holder. In the meantime, it looks like Orthoscopics are the best
> > currently available eyepiece for planetary use.
>
> This is an interesting thread and I hope that I can learn something from
> all of this since planets are my prime interest.
> I am still left with one question regarding planetary eyepieces, one
> important item that has not been touched on so far is the high quality
> of polish and coatings, this is what makes Zeiss, Pentax and Tak orthos
> so special and I am not certain if one can ever find that level of
> quality in polish and coatings in a Monocentric Triplet or a similar
> inexpensive offerings from Edmund or other sources.
>
> Thanks,
> Vahe
Hi,
I do not believe that the actual Monocentric eyepiece is even available (yet).
It is quite different from the Hastings and Steinheil triplets in the Edmund
catalog. If there WERE a real Monocentric eyepiece available, I suspect that
it would be made by Zeiss or some other maker with similar quality of
manufacture. Also, some of these designs are better for some designs of
telescopes than for others. If you can find a copy, please DO look at J. B.
Sidgwick's Amateur Astronomer's Handbook, in the section on oculars, and in his
Observational Astronomy for Amateurs, in the sections on planetary
observations. They are dry as toast but, IMHO, very accurate. What is
currently generally available for your purpose would probably be very
high-grade Orthoscopics. I checked the Markus Ludes used equipment site, and
the used Pentax, Nikon, and Zeiss orthos were going for over $400. I hope that
more affordable planetary oculars will be made available, even at the cost of
some FOV.
Bill.
lude...@my-deja.com
> high-grade Orthoscopics. I checked the Markus Ludes used equipment
site, and
> the used Pentax, Nikon, and Zeiss orthos were going for over $400. I
hope that
> more affordable planetary oculars will be made available, even at the
cost of
> some FOV.
>
> Bill.
Bill, only the NIKON are really expensive, but only because I paid that
money my self to RVR Optical plus shipping and taxes, Pentax orthos are
okay, the Zeiss on my side with $ 120 are not such expensive
best wishes
Markus
TMBack
>The 5mm Pentax ortho is the only one I'm missing and,
>lacking finding one, where can I find out more about the
>Nikons as a possible substitute to use with my FS102?
Alas, the .965" Nikon orthos are long out of production.
They are virtually impossible to find on the used market.
Expect $300 to $400 used. Just find a Pentax 5mm, and
you will save a lot of time and money, and get 95%
of the performance.
Thomas
William H. Foley, Sr.
I stand corrected. The Zeiss are a good deal, then. I hope everyone
following this thread does check out your site. Thanks for the correction!
Bill.
Larry Brown
> I am still left with one question regarding planetary eyepieces, one
> important item that has not been touched on so far is the high quality
> of polish and coatings, this is what makes Zeiss, Pentax and Tak orthos
> so special and I am not certain if one can ever find that level of
> quality in polish and coatings in a Monocentric Triplet or a similar
> inexpensive offerings from Edmund or other sources.
To begin with, the Edmund Scientific triplets are not inexpensive. They
are in fact the most expensive lenses that I have bought for my homemade
eyepiece construction. Their Hastings triplet is made of three elements
computer-designed to interact with each other, in order to eliminate pin
cushion distortion and chromatic and spherical aberrations (according to
Edmund.) They are AR coated with MgF2. Their Steinheil are made from a
low-index center element cemented between two high-index outer elements for
exceptional correction.
If you add a single plano-convex lens on top (as the eyelens) you have an
orthoscopic eyepiece. This makes perfect sense since a Hastings triplet is
going to be f/2 or f/1.5. This means that an 8mm diameter lens will give you a
focal length of 12mm (f1.5) or 16mm (f2). The f2 eyepiece will ususally give
you less distortion. If you want a higher power lens, the diameter of the
triplet becomes ridiculously small, so you add a single PCX lens (or any
positive miniscus) to increase the focal length. Putting a 6mm f/2 single
lens in front of an 8mm f/2 triplet will give you a lens with a focal length
of 7mm--a classic orthoscopic configuration. (12mm x 16mm) divided by (12mm
+16mm) = 192/28 = 6.9. These figures are approximate-I did not subtract the
tiny distance between primary planes.
The value of a monocentric is that you have only two air-to-glass
surfaces. I seem to remember that early monocentric eyepieces were not
cemented triplets, but a single piece of glass, cut from a rod of crown glass
with spherical ends. Later ones were made from a crown component sandwiched
between two outer flint components ("Amateur Astronomer's Handbook", Sidgwick,
pp 113-114).Because of spherical aberation they cannot be used with telescopes
shorter than f/5. The field of view is about 25 degrees, but if you are
observing planets, who cares?
The popularity of the "spacewalk" wide-field eyepiece has pushed orthos
and other narrow field eyepieces right off the market and made them harder to
find. I admit that when I use my 2-inch ultra-wide erfle with a 2-inch barlow
and see closeup planetary detail on Jupiter and all four moons at the same
time with a few background stars thrown in--I get a thrill not unlike when I
was 10 years old and first looked through a telescope. Guess I'm spoiled for
the panoramic views, but if I want to do detailed drawings, I use my
thirty-year-old set of Meade research-grade Orthoscopics. They still can't be
beat.
Clear eyepieces. LB
Mark D'Ambrosio
(The rare glass comment)
Relating to Tom Back's last comments, I see (Have found) that even the
5mm. Pentax Ortho has recently become a real bugger to find. (Probably
the rarest of the bunch)
The 5mm. Nikon Ortho is virtually imposssible to find (Just ask Gary
McClaren)
I'm sure Gary has begged about 40 times to get your 5mm Nikon from you
Tom.
Gary's a great guy though, and I hope he does find himself a 5mm Nikon.
Somewhere, I remember someone mentioning that the old Meade Research
Grade Orthos were made in the same factory as the Nikon Orthos. (Is this
true, or not? Can anyone comment?)
Robert Adelman, and a few others have also mentioned to me that the
GOTOH Orthos were a mighty fine eyepiece also.
(Might have to fly out to Japan for these though!) Mark
Bill Becker
I had a heck of a time finding the 5mm Pentax. Finally posted a want ad
on Astromart and got one for about US$170. If Tom's assessment is
correct re 95% of the performance of the Nikon, and I don't doubt that
one bit, I'm glad I didn't have to pay 95% of a Nikon's price. The
Nikon's I've see advertised are running +US$400. As Mike M. stated so
appropriately, I think I'll settle for my Pentaxes. ;^)
Re GOTOs....I came this close(holding my fingers really close together)
to acquiring a 25mm Kellner.(It was already sold) Picked up a
Tele-optics 18mm and love it.
Best regards,
Bill
Vahe Sahakian
> > money my self to RVR Optical plus shipping and taxes, Pentax orthos are
> > okay, the Zeiss on my side with $ 120 are not such expensive
> > Markus
>
> I stand corrected. The Zeiss are a good deal, then. I hope everyone
> following this thread does check out your site. Thanks for the correction!
Markus will definitely clarify this, but $120 for a Zeiss orthos
generally implies the older .965" barrel eyepieces, the more recent ones
with 1.25" barrel generally go for over $400 used, that is, if you can
find one.
As for difference in quality between these two series I do not have any
facts and never had a chance to compare them side by side, from what I
hear the more recent 1.25" eyepieces are of higher overall quality and
therefore disappear instantly when offered for sale.
Thanks,
Vahe
Chris1011
facts and never had a chance to compare them side by side, from what I
hear the more recent 1.25" eyepieces are of higher overall quality and
therefore disappear instantly when offered for sale.>>
Since Astro-Physics was a distributor for these oculars several years ago, I
obtained the specs and internal construction details from Zeiss for both the
older series and the newer ones. The old .965 Orthos were made specifically for
microscopes, where the F ratio is around F20, although they are useable with
faster F ratio telescopes. The newer 1.25" design uses rare earth glasses for
better correction over a wider field with faster F ratios. They were designed
specifically for telescopes. There is a significant increase in light
transmission with the T coatings on the new ones vs. single layer mag-fluoride
on the old design. Those are the main differences. Workmanship and glass
internal quality is probably the same for both.
Roland Christen
Mike McIsaac
Bill, you got a bargain at $170 for that 5mm Pentax of yours. I have
12.5mm and 25mm Japan Special Optics orthos in 1.25" barrels. I was
absolutely gobsmacked by the planetary performance of these oculars. I
mentioned them in a message to Markus Ludes and he replied that the
lenses for these were made by Nikon. THAT explains their performance!
The JSO's are almost as rare as the Nikons. And no, mine are not for
sale.
Clear, steady skies!
Mike McIsaac
60*N 150*W
In article <3A0A1133...@rmisp.com>,
--
*********************************************
186,000 miles per second: its not just a good
idea, its the law!
*********************************************
lude...@my-deja.com
1, I used really all connections to find NIKON and Pentax and Goto
Orthos all over europe and by just any japanese , taiwanese and Hong
Kond Dealer , absolutly none. Even the Japanese amateuers starting now
to make highest offers to get one or another.
NIKON Orthos: The only source I know (excapt my little stock) is RVR
Optical in New York. I dont know and nobody else know his sources,
where he comes across from time to time with such eyepieces and
telescopes.
Pentax Orthos: The absolutly last stock from japan and from us was sold
to GCS Astronomical, John Biggs, if somebody have a few left than only
he.
We self have available only the 7 mm ortho and no others.
Another last chance: used market.
Zeiss Abbe Orthos 1.25": only used market, but soem dealers doing quite
big pressure to Zeiss , but nobody knows if they ever again start an run
Zeiss Jena 0.965" Orthos ( still worldclass eyepieces) coming from time
to time on the used market here in Germany, all you need to do is to
wait and know where you can get them
If you are looking for one or another of above eyepieces, take daily an
look on my second hand list or left an notice to me , that you like to
get this or that eyepiece.
good luck to all
Markus
In article <8udj4q$6g7$1...@nnrp1.deja.com>,
Chris1011
(The rare glass comment)>>
Rare earth not rare glass. This includes the Lanthanum series of crowns and
flints. These high index glasses are chosen to reduce the curvature on the lens
surfaces for any given focal length, thus allowing for better control of the
Sidel aberrations.
Roland Christen
TMBack
>I smell JJ Goss
You smell JJ Goss? Oh, that must be awful. Heaven
forbid! Please, don't bring his name up again, he might
come back! :-)
Thomas Back
TMB Optical
TMBack
>The 5mm. Nikon Ortho is virtually imposssible to find
>(Just ask Gary McClaren) I'm sure Gary has begged
>about 40 times to get your 5mm Nikon from you
>Tom.
Almost 40 times.
>Gary's a great guy though, and I hope he does find
>himself a 5mm Nikon.
Yes, he is. I hope he finds that 5mm Nikon he is
looking for.
>Somewhere, I remember someone mentioning that the
>old Meade Research Grade Orthos were made in the
>same factory as the Nikon Orthos
I don't know where Meade had their Research Grade
orthos made, but I can tell you that they have nothing
in common, and that includes the design and coatings,
not to mention performance -- not that the Research
Grade orthos were not excellent eyepieces.
Thomas
Bill Becker
close to acquiring a JSO 25mm Kellner. I don't know if GOTO even made
Kellners. Sorry about that.
Bill
Bill Becker wrote:
>
> Hi Mark,
>
> I had a heck of a time finding the 5mm Pentax. Finally posted a want ad
> on Astromart and got one for about US$170. If Tom's assessment is
> correct re 95% of the performance of the Nikon, and I don't doubt that
> one bit, I'm glad I didn't have to pay 95% of a Nikon's price. The
> Nikon's I've see advertised are running +US$400. As Mike M. stated so
> appropriately, I think I'll settle for my Pentaxes. ;^)
>
> Re GOTOs....I came this close(holding my fingers really close together)
> to acquiring a 25mm Kellner.(It was already sold) Picked up a
> Tele-optics 18mm and love it.
>
> Best regards,
> Bill
>
> Mark D'Ambrosio wrote:
> >
> > Ooh Roland, I smell JJ Goss showing up with this last post of yours! :-)
> > (The rare glass comment)
> > Relating to Tom Back's last comments, I see (Have found) that even the
> > 5mm. Pentax Ortho has recently become a real bugger to find. (Probably
> > the rarest of the bunch)
> > The 5mm. Nikon Ortho is virtually imposssible to find (Just ask Gary
> > McClaren)
> > I'm sure Gary has begged about 40 times to get your 5mm Nikon from you
> > Tom.
> > Gary's a great guy though, and I hope he does find himself a 5mm Nikon.
> > Somewhere, I remember someone mentioning that the old Meade Research
btwir...@my-deja.com
According to the Zeiss (Jena) Literature Publ.No.:56-15/274/1/94 the
Jena orthoscopic eyepieces were designed for f /10. Perhaps this is an
error, but it's unlikely that "the old .965 Orthos were made
specifically for microscopes". The typical Jena microscope eyepieces of
the time had a different barrel diameter, were not orthoscopic, and
were not offered in a wide range of focal lengths.
Brian
Chris1011
Jena orthoscopic eyepieces were designed for f /10. Perhaps this is an
error, but it's unlikely that "the old .965 Orthos were made
specifically for microscopes". The typical Jena microscope eyepieces of
the time had a different barrel diameter, were not orthoscopic, and
were not offered in a wide range of focal lengths.
>>
You are probably correct and my information about the origins of the Jena
Orthos is incorrect. The performance differences, however, are as I described
them. The origins of the Ortho design go back to the microscope. It was created
to eliminate distortion (pincussion and Barrel) so that the field would be
even, and accurate measurements with reticles could be achieved. The design
works best with long focal ratios, and begins to show spherical undercorrection
at F ratios faster than F10. The newer 1.25" Abbe Ortho uses high index rare
earth glass to minimize this undercorrection up to F8 focal ratios.
The old design used single layer mag-fluoride coatings with total transmission
that varied from 75% at the ends of the blue spectrum, 88% in the green and
peaked at 90% in the deep red end of the spectrum. The newer 1.25" Abbe Orthos
have greater than 97% transmission over the visible spectrum with a slight
falloff to 90% in the far violet.
There was also a 2x Barlow lens design, but we were not able to obtain any, and
I don't know how many were actually made. I believe it did not make it past the
prototype stage, but Baader tells me that the one he has tested was superb. To
this day, he is trying to get at least some of those made, but no luck so far.
Roland Christen
btwir...@my-deja.com
chri...@aol.com (Chris1011) wrote:
snip
I suspect the 1.25" 2x barlow utilized the same element as the M44 2x
barlow, but I'm not by any means certain. I have one of the M44
barlows, but unless they had a different part number in the distant
past, no more than 4 entered the states via Seiler Instrument.
William H. Foley, Sr.
> In article <20001108194229...@ng-ch1.aol.com>,
> chri...@aol.com (Chris1011) wrote:
> Roland,
>
> According to the Zeiss (Jena) Literature Publ.No.:56-15/274/1/94 the
> Jena orthoscopic eyepieces were designed for f /10. Perhaps this is an
> error, but it's unlikely that "the old .965 Orthos were made
> specifically for microscopes". The typical Jena microscope eyepieces of
> the time had a different barrel diameter, were not orthoscopic, and
> were not offered in a wide range of focal lengths.
>
> Brian
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.
Hi,
I should think that orthoscopic eyepieces for microscopes would be a bit of
overkill, however it is certainly something that is probable where highest
quality is desired.
However, I believe we are getting off the subject of best eyepiece design
for planetary work, and the originator of this thread might at this point be
wondering what this has to do with the original question.
Among eyepieces currently available, I believe that the best planetary
eyepiece is indeed the best Ortho, however, in several publications, the
best planetary design has been given as the Kepler EP, which is just a
single lens, with a small field stop to minimize all the aberrations
inherent in the lens and the objective. These are very old publications
(such as Webb's Celestial Objects for Common Telescopes and the Sidgwick
Amateur Astronomy books), but, if absolute best planetary is desired even
though the FOV is very small, then the Kepler would be a good choice. The
books cited are from a time when most amateur working scopes were long
refractors.
Bill.
Mark Hammons
>
> Hi Alan,
>
> >So, should I be saving my nickels and dimes <g>?
>
> All I can say at this point is that's a good possibility.
>
> Thomas
Thomas,
Could you or somebody give a rundown on :
1) Hastings Triplet
2) Steinheil Triplet.
3) Monocentric (triplet??)
I thought a monocentric was either a Hastings or a Steinheil?
Mark Hammons
Bob Luffel
> There was also a 2x Barlow lens design, but we were not able to
obtain any, and
> I don't know how many were actually made. I believe it did not make
it past the
> prototype stage, but Baader tells me that the one he has tested was
superb. To
> this day, he is trying to get at least some of those made, but no
luck so far.
>
> Roland Christen
>
I suspect the 1.25" 2x barlow utilized the same element as the M44 2x
barlow, but I'm not by any means certain. I have one of the M44
barlows, but unless they had a different part number in the distant
past, no more than 4 entered the states via Seiler Instrument.
Brian
Zeiss did produce some of the matched 2X barlows (matched to the Abbe's) - I
do not know how many were produced.
The barlow lens is quite different from the older M44 barlow. The curves are
obviously different, the coatings different (multicoatings) and housing is
different (and parfocal with the bare eyepieces). It is a very good barlow and
an excellent match to the 1.25" Abbes.
Bob Luffel