Meade 7" Maksutov/ 8" SCT comparison question
François Duhem
I'm new to amateur astronomy and until now, I have only
observed planets (jupiter, saturn, venus and mars) and some
deep sky objects (M42, M31) with my _Leica apo 77 televid_
spotting scope. While the images of saturn and jupiter were
pretty good for me ( it isn't meaningful because I never looked
through another scope), I was limited by the maximum magnification
available (60x, leica doesn't sell higher power occular). For example,
the only details I can see on Jupiter are the two horizontal bands, and I
think
I could discern the poles. On Saturn, I could not see the Cassini division.
Briefly said, I went quickly from positive amazement to see details
where the naked eye could only see bright points to an increasing
frustration,
specially when I compared what I saw to the observation reports given
by some of you. Arrived to this point I can ask you my questions.
1) Is it possible to improve the images delivered by my scope with
shorter focal occulars ? I know that the highest practical magnification
for an 77mm apo should be about 150x, but I don't know how to adapt
other occulars than the Leica to my scope.
2) I seriously think about buying a real astronomy telescope, and I have
been
tempted by two of them: the Mak 7" and the SCT 8" from Meade. You will
surely say that they are not in the same category of price, but this is
not
the "decision making" factor for me: it is more a balance between
aperture and
ease of handling and setup that I'm looking for. My question is: does
anyone of you have looked
through these two scopes and noticed a difference in the image quality
?
Many people claim that for a given aperture, the Maksutov designs have
far
better image quality than SCT's, do you agree with this, and can you
say for
what reason ?
I know my questions are not new, but I'm about to buy my new telescope, and
I really need the objective advice of some experienced amateurs (my dealer
will just tell me to buy the Mak design because it's way more pricey).
I thank you in advance, and I excuse myself not to master english as well
as you: French people always had troubles with foreign languages.
Best regards,
François Duhem.
Michael Edelman
"François Duhem" wrote:
>
....
> 2) I seriously think about buying a real astronomy telescope, and I have
> been
> tempted by two of them: the Mak 7" and the SCT 8" from Meade.
The Mak is optically far better. Both are less than ideal mechnically,
IMHO.
Rockett Crawford
Michael Edelman wrote:
I disagree. The Mak is only subtly better on high magnification objects and
both are good mechanically.
Rockett Crawford
Bill Becker
Rockett Crawford wrote:
I agree with you about the optics. Also, the 7" is one big heavy monster. I find
I use it a lot less than my more portable scopes.
Best regards,
Bill
Rockett Crawford
Bill Becker wrote:
> Rockett Crawford wrote:
> >
> > I disagree. The Mak is only subtly better on high magnification objects and
> > both are good mechanically.
> >
> > Rockett Crawford
>
> I agree with you about the optics. Also, the 7" is one big heavy monster. I find
> I use it a lot less than my more portable scopes.
> Best regards,
> Bill
The larger scopes definitely are heavier and require more cool down
time.
Also I would agree that the their mechanical designs are less than
ideal for astrophotography and imaging if they aren't modified
because the mirrors tend to shift during exposures(or integrations).
Modification however is easy for scopes that require it to
secure the mirror from movement.
Visually they are fine without any modification.
Rockett Crawford
Pablo
by side and I found that the Celestar (1997 vintage) was a bit sharper and
of course brighter. Celestron
has been putting out some good SCTs, and that 1" extra apperture over the 7"
Mak
is going to make a difference in resolution if it's well collimated of
course.
Maksutov far better image quality?
I think "most" of those people who say a Mak is better are either repeating
what someone else
said or they have a Mak. So, if you get an optically good SCT then it should
be a little better
than the Mak in good seeing conditions.
-Pablo
Jesse Robinson
I own a Meade 8" SCT. The scope is a little over ten years old. A couple of
months ago, I looked through a Meade 7" Maksutov-Cassegrain at a start party.
We we set up approximately 50' from each other. The image was much better in
the 7". The image was so much better that I ordered the INTES 9"
Maksutov-Cassegrain a couple weeks later. The new scope is scheduled to arrive
before the end of the year.
jess
"François Duhem" wrote:
> Hello to everyone,
> 2) I seriously think about buying a real astronomy telescope, and I have
> been tempted by two of them: the Mak 7" and the SCT 8" from Meade. You
> will surely say that they are not in the same category of price, but this is
> not
> the "decision making" factor for me: it is more a balance between
> aperture and ease of handling and setup that I'm looking for. My question is:
François Duhem
some of you seem to think that there
is no comparison in optical quality between both designs, and other
tend to say that if a difference exist, it must be very small.
So I'm still not sure what to buy, but the balance would
be in favor of the SCT, because it appears that the
qual/price ratio is more favorable for this design.
I have another question, the F/D ratio of the Meade's Mak
is significantly higher than the SCT's. Can you tell me
what are the difference in image quality between 2 scopes
of different focal length at the same magnification ( by choosing
a shorter focal occular for the one which has a shorter focal),
will the long focal instrument have a more contrasty image ?
Regards,
François.
Rockett Crawford
Yes, the longer focal length scope with a correspondingly
higher focal length eyepiece will generally give a little bit
better view.
The Mak's field of view will be slightly flatter also than
the SCT which has a little more field curvature. This
means that the stars at the edge of the field of view will
tend to be a little less distorted and in focus if you have
good eyepieces.
Again, the differences are very subtle. These differences
tend to be exaggerated in this ng. It won't knock your
socks off.
The drawback is if you are looking for more of
a rich field viewing of deep sky objects or if you
want to get into photography. The higher f/ratios
of the Mak are somewhat of a drawback in those areas.
take care,
Rockett Crawford
JMc
> Rockett Crawford wrote:
>
> Yes, the longer focal length scope with a correspondingly
> higher focal length eyepiece will generally give a little bit
> better view.
Does it make sense to compare performance at different magnifications?
In a real comparison at the same magnification, the scope with the
darker sky and more contrast is the one I want. Contrast is not just a
function of the basic optical design. Things like baffles, surface
smoothness, and coatings all contribute significantly to the contrast we
see at the eyepiece.
>
> The Mak's field of view will be slightly flatter also than
> the SCT which has a little more field curvature. This
> means that the stars at the edge of the field of view will
> tend to be a little less distorted and in focus if you have
> good eyepieces.
Are you suggesting we make up for the deficiencies in the SCT design by
spending 2X-3X more for eyepieces? Seems like a false economy.
>
> Again, the differences are very subtle. These differences
> tend to be exaggerated in this ng. It won't knock your
> socks off.
I agree that many of these differences are subtle. But it's the
subtleties over time that lead to growing annoyance, or great enjoyment.
> The drawback is if you are looking for more of
> a rich field viewing of deep sky objects or if you
> want to get into photography. The higher f/ratios
> of the Mak are somewhat of a drawback in those areas.
Bogus argument alert. There are f/10 and even f/6 MCTs, and most MNTs
are f/6. Just because Meade doesn't make these is not a reason to ignore
them. I can see the entire Pleiades cluster in my f/10 MCT at 35X, and
the stars are good to the edge of the field using a cheapo $110 Erfle eyepiece.
Jim McSheehy
Bill McHale
: Hello to everyone,
: I'm new to amateur astronomy and until now, I have only
: observed planets (jupiter, saturn, venus and mars) and some
: deep sky objects (M42, M31) with my _Leica apo 77 televid_
: spotting scope. While the images of saturn and jupiter were
: pretty good for me ( it isn't meaningful because I never looked
: through another scope), I was limited by the maximum magnification
: available (60x, leica doesn't sell higher power occular). For example,
: the only details I can see on Jupiter are the two horizontal bands, and I
: think
: I could discern the poles. On Saturn, I could not see the Cassini division.
: Briefly said, I went quickly from positive amazement to see details
: where the naked eye could only see bright points to an increasing
: frustration,
: specially when I compared what I saw to the observation reports given
: by some of you. Arrived to this point I can ask you my questions.
: 1) Is it possible to improve the images delivered by my scope with
: shorter focal occulars ? I know that the highest practical magnification
: for an 77mm apo should be about 150x, but I don't know how to adapt
: other occulars than the Leica to my scope.
It might be possible, but I am not sure if you really want to take this
route as you are still compromising.
: 2) I seriously think about buying a real astronomy telescope, and I have
: been
: tempted by two of them: the Mak 7" and the SCT 8" from Meade. You will
: surely say that they are not in the same category of price, but this is
: not
: the "decision making" factor for me: it is more a balance between
: aperture and
: ease of handling and setup that I'm looking for. My question is: does
: anyone of you have looked
: through these two scopes and noticed a difference in the image quality
: ?
: Many people claim that for a given aperture, the Maksutov designs have
: far
: better image quality than SCT's, do you agree with this, and can you
: say for
: what reason ?
Ok, in either of these scopes, provided the optics are half decent (and
that describes more Meade Optics these days... half decen :)), you are
going to see a wealth of detail that is simply far beyone the reach of
your current spotter. Now as for the performance of the two scopes:
In general Maksutovs tend to have better optics than the SCTs; it is not
that the design in inherintly superior (though if both scopes use
spherical mirrors I think it is possible that the Rumak-Maksutov will
outperform the Spherical mirror SCT, but I doubt the Meade Mak is a Rumak
so we don't need to worry about that.) rather the Maksutov Corrector is
shperical while the SCT corrector has a rather complicated curve. As a
result the Maksutov corrector is a bit easier to make well; also the
longer focal length might be a performance enhancer as well. Thus in
practice a Maksutov will tend to have better optics, but if you happen to
get one of the better quality SCTs you will match or exceed the Maksutov
performance. Also the Maksutov is much heavier than the SCT.
: I know my questions are not new, but I'm about to buy my new telescope, and
: I really need the objective advice of some experienced amateurs (my dealer
: will just tell me to buy the Mak design because it's way more pricey).
: I thank you in advance, and I excuse myself not to master english as well
: as you: French people always had troubles with foreign languages.
: Best regards,
Actually your English is fine; much better than my French (Je ne parle pas
Francais tres bien). In terms of practical advise, all I can suggest is
see if there are any star parties you can go to. The best way to decide
what type of Telescope you really want is to look through plenty. Another
reasonably affordable and somewhat more transportable option you might
consider is getting one of the Russian 6" Maksutovs. They are very
compact and reasonably light and will give good performance on the
planets.
--
Bill
***************************************************************************
People who eat natural foods die from natural causes.
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Home page - http://www.gl.umbc.edu/~wmchal1
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gkigera...@my-deja.com
tri...@my-deja.com wrote:
>
>
> > Rockett Crawford wrote:
> >
> > Yes, the longer focal length scope with a correspondingly
> > higher focal length eyepiece will generally give a little bit
> > better view.
>
> Does it make sense to compare performance at different magnifications?
> In a real comparison at the same magnification, the scope with the
> darker sky and more contrast is the one I want. Contrast is not just a
> function of the basic optical design. Things like baffles, surface
> smoothness, and coatings all contribute significantly to the contrast
we
> see at the eyepiece.
In theory most visual comparisons should be made at the same mag, but
in practice it could be the case that you have a limited selection of
eyepieces on hand.
On the contrast point, do you have any information on the systems being
discussed? Is the Meade Mak well baffled? Poorly baffled? How does it
compare to various SCT offerings?
>
> >
> > The Mak's field of view will be slightly flatter also than
> > the SCT which has a little more field curvature. This
> > means that the stars at the edge of the field of view will
> > tend to be a little less distorted and in focus if you have
> > good eyepieces.
>
> Are you suggesting we make up for the deficiencies in the SCT design
by
> spending 2X-3X more for eyepieces? Seems like a false economy.
>
The point I got was not a suggestion to spend more on eyepieces - I
thought the comment was that you will need good eyepieces to see a
noticeable difference in field curvature.
> >
> > Again, the differences are very subtle. These differences
> > tend to be exaggerated in this ng. It won't knock your
> > socks off.
>
> I agree that many of these differences are subtle. But it's the
> subtleties over time that lead to growing annoyance, or great
enjoyment.
>
Do you mean the annoyance of nitpicking someone's comments by ignoring
the point they are trying to make?
> > The drawback is if you are looking for more of
> > a rich field viewing of deep sky objects or if you
> > want to get into photography. The higher f/ratios
> > of the Mak are somewhat of a drawback in those areas.
>
> Bogus argument alert. There are f/10 and even f/6 MCTs, and most MNTs
> are f/6. Just because Meade doesn't make these is not a reason to
ignore
> them. I can see the entire Pleiades cluster in my f/10 MCT at 35X, and
> the stars are good to the edge of the field using a cheapo $110 Erfle
eyepiece.
>
Other Maks are not being ignored - they are just not the topic of this
thread. You are right about the rich field argument - just pick the
right eyepiece to get a low power view. Even with photography a higher
f/ratio is becoming less of an issue due to the use of focal reducers.
From a practical perspective, however, if your intent is CCD or film,
you will be better off with a lower f/ratio.
Sent via Deja.com http://www.deja.com/
Before you buy.
Rockett Crawford
JMc wrote:
> > Rockett Crawford wrote:
> >
> > Yes, the longer focal length scope with a correspondingly
> > higher focal length eyepiece will generally give a little bit
> > better view.
>
> Does it make sense to compare performance at different magnifications?
No, that's why I said a higher focal length scope with a higher
focal length eyepiece. Magnification is found by a ratio of
scope fl to ep fl. Example 1200mm/10mm = 120x.
A higher fl scope and higher fl ep give the same magnification.
Example: 2400mm/20mm = 120x.
> In a real comparison at the same magnification, the scope with the
> darker sky and more contrast is the one I want. Contrast is not just a
> function of the basic optical design. Things like baffles, surface
> smoothness, and coatings all contribute significantly to the contrast we
> see at the eyepiece.
Contrast is a factor but other things such as resolving power,
image brightness, etc... also are factors.
> > The Mak's field of view will be slightly flatter also than
> > the SCT which has a little more field curvature. This
> > means that the stars at the edge of the field of view will
> > tend to be a little less distorted and in focus if you have
> > good eyepieces.
>
> Are you suggesting we make up for the deficiencies in the SCT design by
> spending 2X-3X more for eyepieces? Seems like a false economy.
I wouldn't call the slight field curvature in SCTs a significant
"deficiency" in design for observing.
I said "good eyepieces" to avoid the effects that bad wide
field eyepieces introduce.
BTW, talk to a large dobsonian owner about the "false economy"
of good eyepieces to reduce edge distortions.
> > Again, the differences are very subtle. These differences
> > tend to be exaggerated in this ng. It won't knock your
> > socks off.
>
> I agree that many of these differences are subtle. But it's the
> subtleties over time that lead to growing annoyance, or great enjoyment.
I disagree. They are subtle and not that big of a deal, especially
in the long run.
>
> > The drawback is if you are looking for more of
> > a rich field viewing of deep sky objects or if you
> > want to get into photography. The higher f/ratios
> > of the Mak are somewhat of a drawback in those areas.
>
> Bogus argument alert. There are f/10 and even f/6 MCTs, and most MNTs
> are f/6. Just because Meade doesn't make these is not a reason to ignore
> them.
We are talking about the Meade so it is not a "bogus argument."
> I can see the entire Pleiades cluster in my f/10 MCT at 35X, and
> the stars are good to the edge of the field using a cheapo $110 Erfle eyepiece.
Glad to hear it.
take care,
Rockett Crawford
WHALEN44
tend to be exaggerated in this ng. It won't knock your socks off.>>>
Hi Rockett,
As far as Meade goes, you are probably right. But have you ever looked through
a high quality MCT or MNT's like a AP or TEC or Ceravolo etc. with <30%
obstructions and compared it side by side with a SCT?
Richard Whalen
whal...@aol.com
"Time spent observing the heavens is not deducted from your lifespan"
Rockett Crawford
WHALEN44 wrote:
> Rockett wrote>> > Again, the differences are very subtle. These differences >
> tend to be exaggerated in this ng. It won't knock your socks off.>>>
>
> Hi Rockett,
>
> As far as Meade goes, you are probably right. But have you ever looked through
> a high quality MCT or MNT's like a AP or TEC or Ceravolo etc. with <30%
> obstructions and compared it side by side with a SCT?
>
No, because no one I know of is using them and I don't see them
at star parties. I have looked through many APOs and other "premium"
refractors and I come away with the same conclusion.
Rockett Crawford
WHALEN44
Than I think you don't know from where you speak.
You are perpetuating a belief based on nothing factual. I'm sure you have not
compared a 8" SCT to a 8" APO, ot a 7" Meade MCT to a 7" APO.
Or have you even done a side by side comparrision of a 5" SCT to a 5" APO? The
differences are very significant.
You are making statements based on what? Taking a quick look through a 4" or 5"
APO and later a 8" SCT? Sorry, not a valid test method to use if you are going
to turn around and spout the results as fact in a public forum. You are making
judgements about scopes that by your own admission you have never seen or used.
Steady Skies,
Richard Whalen
Rockett Crawford
WHALEN44 wrote:
> Hi Rockett,
>
> Than I think you don't know from where you speak.
> You are perpetuating a belief based on nothing factual. I'm sure you have not
> compared a 8" SCT to a 8" APO, ot a 7" Meade MCT to a 7" APO.
>
Non Sequitur. I have compared 4 inch APOs to 4 inch SCTs and ETXs.
Not much difference really. It's there but not that big of a deal.
I've also looked through many other scopes. That is one thing that is
nice about going to huge star parties like the annual Texas Star Party
year after year.
>Or have you even done a side by side comparrision of a 5" SCT to a 5" APO? The
>differences are very significant.
I disagree. A good SCT is not that much different. The APO has better edge
sharpness and a little better contrast.
>You are making statements based on what? Taking a quick look through a 4" or 5"
>APO and later a 8" SCT? Sorry, not a valid test method to use if you are going
>to turn around and spout the results as fact in a public forum. You are making
>judgements about scopes that by your own admission you have never seen or used.
No, that's not true at all.
take care,
Rockett
Allister
Does your comment refer to all mak-cass or just the Meade
design/implementation of a mak-cass? The Meade design is not an
outstanding example of what can be done with a mak-cass (especially at
38% CO), while the Intes Micro, AP and TEC are.
Having said that and having owned both SCTs and Maks (including the
Meade version) I would prefer owning a 7" Meade Mak over an 8" sct.
To clarify ownership issues, I own neither at the moment.
Allister
a...@ais.net
>
>Maksutov far better image quality?
>I think "most" of those people who say a Mak is better are either repeating
>what someone else
>said or they have a Mak. So, if you get an optically good SCT then it should
>be a little better
>than the Mak in good seeing conditions.
>
>-Pablo
>
>
>
> My question is: does
>> anyone of you have looked
>> through these two scopes and noticed a difference in the image
>quality
>> ?
>> Many people claim that for a given aperture, the Maksutov designs have
>> far
>> better image quality than SCT's, do you agree with this, and can you
>> say for
>> what reason ?
>> I know my questions are not new, but I'm about to buy my new telescope,
>and
>> I really need the objective advice of some experienced amateurs (my dealer
>> will just tell me to buy the Mak design because it's way more pricey).
>> I thank you in advance, and I excuse myself not to master english as well
>> as you: French people always had troubles with foreign languages.
>> Best regards,
>> François Duhem.
>>
>>
>
>
Paul Hyndman
whal...@aol.com (WHALEN44) wrote:
> As far as Meade goes, you are probably right. But have you ever
> looked through a high quality MCT or MNT's like a AP or TEC or
> Ceravolo etc. with <30% obstructions and compared it side by side
> with a SCT?
I realize this is drifting from the poster's original query, and I
apologize for taking it even further off topic but...
Just my $0.02 (and no "slam" intended). There is no way to say it
without seeming blunt, but let me delicately suggest that the design of
the Meade MCT places it in an entirely "different" field than the above
instruments.
I personally love designs that "push it to the max" and am anxiously
awaiting the outcome of Valery (Aries) and Roland's joint endeavor with
a 10" (and hopefully 12" too) MCT.
Valery told me that Aries is providing 1/10th wavefront optics with a
23% CO at f14.6 for these MCTs, while Astro-Physics will be doing the
mechanicals. These will indeed be a very unique breed of instruments
that will doubtlessly be compared to the prevailing SCTs, but if a
viewer honestly cannot see a difference with a much smaller CO, much
smoother and higher quality optics, zero image shift etc. etc... then
yeah... he probably shouldn't spend more!
Gee Francois, I'm sorry this got so far away from your original
question! With the choices you presented though, you probably would be
happier and far better served with the SCT.
Clear Skies and Happy Holidays!
-Paul
--
Paul Hyndman pghy...@yahoo.com Madison, CT
WHALEN44
Well I guess we are just going to have to disagree:-) I assume you compared a
Meade 4" SCT to a 4" APO and you are now judging everything on that one
comparrision? If so, I would guess one or more of the following:
1. Best 4" SCT ever made by Meade
2. Worst 4" APO made by whoever
3. Lousy seeing conditions (which is most of the time at TSP).
4. Poor eyesight?
I have been to TSP myself several times since the early 1980's along with many
other major star parties. I really don't think TSP is the place to judge
optical quality most of the time as the seeing conditions at the Prude Ranch
leave a lot to be desired. Riverside is often better, as is Astrofest and
always WSP. Come down to the Florida Keys, bring your favorite SCT, and I'm
sure someone will be their with a like size high quality APO or MCT or MNT to
compare with. I think you would be surprised......
Clear Skies,
Richard
lude...@my-deja.com
<097D887460C4B040.FA7A402F...@lp.airnews.net>,
Rockett Crawford <Roc...@Audiotel.com> wrote:
>
>
Hi Rockett,
long long time ago a german customer visited in clear evening my shop
and we took 2 scopes out for comparing.
Scope Nr.1: a 5"F/5 cemented achromat (cometfinder)with bad optics
Scope Nr.2: a 5" Takahahsi Fluorite with superb optics.
after 1 hour observing deep sky and planets, the customer told me, he
see now diffrence between the 2 scope , excapt that the achromat have a
little color. He bought the much cheraper achromat and was happy.
His experience and critism remembers me very well to yours
merry christmas
Markus
> WHALEN44 wrote:
>
> > Hi Rockett,
> >
> > Than I think you don't know from where you speak.
> > You are perpetuating a belief based on nothing factual. I'm sure
you have not
> > compared a 8" SCT to a 8" APO, ot a 7" Meade MCT to a 7" APO.
> >
>
> Non Sequitur. I have compared 4 inch APOs to 4 inch SCTs and ETXs.
> Not much difference really. It's there but not that big of a deal.
>
> I've also looked through many other scopes. That is one thing that is
> nice about going to huge star parties like the annual Texas Star Party
> year after year.
>
> >Or have you even done a side by side comparrision of a 5" SCT to a
5" APO? The
> >differences are very significant.
>
> I disagree. A good SCT is not that much different. The APO has better
edge
> sharpness and a little better contrast.
>
> >You are making statements based on what? Taking a quick look through
a 4" or 5"
> >APO and later a 8" SCT? Sorry, not a valid test method to use if
you are going
> >to turn around and spout the results as fact in a public forum. You
are making
> >judgements about scopes that by your own admission you have never
seen or used.
>
> No, that's not true at all.
>
> take care,
> Rockett
>
>
lude...@my-deja.com
whal...@aol.com (WHALEN44) wrote:
> Hi Rockett,
> >
> I have been to TSP myself several times since the early 1980's along
with many
> other major star parties. I really don't think TSP is the place to
judge
> optical quality most of the time as the seeing conditions at the
Prude Ranch
> leave a lot to be desired. Riverside is often better, as is Astrofest
and
> always WSP. Come down to the Florida Keys, bring your favorite SCT,
and I'm
> sure someone will be their with a like size high quality APO or MCT
or MNT to
> compare with. I think you would be surprised......
>
> Clear Skies,
>
> Richard
>
don't ask Rocket to do it. There have been most last years one guy at
WSP with an old C8 , made in 1973 (when Bobb Geoff took his hands on
the C8), with almost perfect optics. This old C8 gave on Jupiter and
Satrun even an superb 7.1" EDF an hard time. Maybe Rockett will find
this guy and ask him to rent his telescope to him, than even the best
of the best MCT would get an hard time. This C8 have had optics as
perfect as an optic can be made.
best wishes
Markus
Rockett Crawford
WHALEN44 wrote:
> Hi Rockett,
>
> Well I guess we are just going to have to disagree:-) I assume you compared a
> Meade 4" SCT to a 4" APO and you are now judging everything on that one
> comparrision? If so, I would guess one or more of the following:
No.
> 1. Best 4" SCT ever made by Meade
> 2. Worst 4" APO made by whoever
> 3. Lousy seeing conditions (which is most of the time at TSP).
> 4. Poor eyesight?
No, I have looked through many different 4 inch refractors,
well as 5 and 6 inch refractors over the years. I own an older
TV Genesis which is similar in quality and I own a 4 inch
Meade SCT .
The seeing at Prude ranch varies from hour to hour sometimes
and occasionally it is excellent all night long.
> I have been to TSP myself several times since the early 1980's along wi
> h many
> other major star parties. I really don't think TSP is the place to judge
> optical quality most of the time as the seeing conditions at the Prude Ranch
> leave a lot to be desired.
As I said, the seeing varies. Sometimes it is excellent all night long.
> Riverside is often better, as is Astrofest and
> always WSP. Come down to the Florida Keys, bring your favorite SCT, and I'm
> sure someone will be their with a like size high quality APO or MCT or MNT to
> compare with. I think you would be surprised......
I doubt it. I think we agree there is a difference in quality. It is just
the magnitude that you ascribe to it that doesn't agree with my experience.
I would suggest for anyone that is genuinely interested to go to
some star parties and see for themselves.
take care,
Rockett Crawford.
Jesse Robinson
Rockett Crawford wrote:
> I would suggest for anyone that is genuinely interested to go to
> some star parties and see for themselves.
>
> take care,
> Rockett Crawford.
I have and I saw a tremendous difference. Perhaps it is because I have poor
quality 8 " SCT Meade and the other individual had a specially good 7 " MCT Meade.
jess
Rockett Crawford
Jesse Robinson wrote:
> Rockett Crawford wrote:
> > IMHO there is no a great deal of difference.
> >
> > I would suggest for anyone that is genuinely interested to go to
> > some star parties and see for themselves.
> >I have and I saw a tremendous difference. Perhaps it is because I have poor
> quality 8 " SCT Meade and the other individual had a specially good 7 " MCT Meade.
Or you might have a good SCT and it could be that something was amiss such as
bad collimation, cool down time, or any of a dozen other possibilities as other people
have mentioned. Who knows.
take care,
Rockett Crawford
Rockett Crawford
Zeus194340 wrote:
> well i bought a 7"LX-200 and before i bought i looked through a 8" LX-200 and
> a 10" LX-200 along with a 5" refractor and although the 10" threw up a bigger
> image it did not resolve anything near the detail as the 7" mak, the refractor
> resolved as good as the mak and i though it was about a tie for optics but the
> mak is bigger so had bigger image resolved as good as a refractor, was a good
> determining factor for me.
Actually an 8 inch and a 10 inch SCT are not going to produce larger images than
the 7 inch Mak if you used the same eyepieces with them. The 7 inch Mak actually
has a longer focal length than both the 8 and 10 inch SCTs and will produce larger
images. 7 inch Mak (2670mm) and 8 inch SCT (2000mm) and 10 inch SCT
(2500mm).
I have personally found that the 7 inch Mak, although it did seem to have a little
better contrast and a flatter field, did not resolve anything better than 8 inch
SCTs and my 11 inch SCT is much better during good seeing. You also seem
to be indicating indirectly that a 10 inch SCT did not resolve anything near the
detail that a 5 inch refractor did (which you said tied the 7 inch Mak). This also
disagrees with my experience during good seeing or better.
take care,
Rockett Crawford
Zeus194340
Jesse Robinson
You are right, there may be another reason for the difference. The SCT is over 10 years
old and the MCT is relatively new.
The SCT was set up first and it was a warm night, so cool down can not explain the
difference. I believe the collimation on the SCT is as good as it will get for this
scope.
I have looked through a few other scopes and not seen the clarity improvements that I saw
in the MCT. The MCT was not the brightest image of Jupiter that I have seen, just the
most detailed, but my experience is limited.
jess
Rockett Crawford
Jesse Robinson wrote:
> Rockett Crawford wrote:
>
> > Jesse Robinson wrote:
> >
> > > Rockett Crawford wrote:
> > > > IMHO there is no a great deal of difference.
> > > >
> > > > I would suggest for anyone that is genuinely interested to go to
> > > > some star parties and see for themselves.
> >
> > > >I have and I saw a tremendous difference. Perhaps it is because I have poor
> > > quality 8 " SCT Meade and the other individual had a specially good 7 " MCT Meade.
> >
> > Or you might have a good SCT and it could be that something was amiss such as
> > bad collimation, cool down time, or any of a dozen other possibilities as other people
> > have mentioned. Who knows.
> >
> > take care,
> > Rockett Crawford
>
> You are right, there may be another reason for the difference. The SCT is over 10 years
> old and the MCT is relatively new.
That shouldn't make any difference unless the scope was abused in some way or
taken apart and put back together improperly, fallen out of collimation, etc...
> The SCT was set up first and it was a warm night, so cool down can not explain the
> difference.
It doesn't make much difference whether the night was warm or not. It takes
a couple of hours for an SCT to adjust to the outdoor temperature once it
is setup to start delivering it's top quality images.
> I believe the collimation on the SCT is as good as it will get for this
> scope.
Are you saying that this particular scope is limited in how well it can
be collimated? If so, it does sound like something is amiss with that
particular scope.
> I have looked through a few other scopes and not seen the clarity improvements that I saw
> in the MCT. The MCT was not the brightest image of Jupiter that I have seen, just the
> most detailed, but my experience is limited.
Actually, there shouldn't have been much difference in the brilliance of Jupiter
between a 7 and an 8 inch scope if similar magnifications were used.
The best view of Jupiter I ever had was through an 18 inch Dobsonian
last October on an exceptionally steady night with Jupiter high in the
sky and late in the night after the sky had thermally stabilized. The view
through my 11 inch SCT also was extremely detailed and pleasing,
one of the best I had ever seen also, although not as good as the
18 inch.
take care,
Rockett Crawford
Capella's Observatory
http://web2.airmail.net/capella
WHALEN44
Help me here with this statement, I'm confused:
>It doesn't make much difference whether the night was warm or not. It takes a
couple of hours for an SCT to adjust to the outdoor temperature once it is
setup to start delivering it's top quality images.>
I think he is saying that the temperature did not drop and was similar to the
enviroment where the scope was stored? (in the below statement)? If so, it
should already be close to thermal equalibrium with the outside air and need
little if any cooldown. It should be in for all practical purposes, ready to
go.
Richard WHalen
Rockett Crawford
WHALEN44 wrote:
> Hi,
>
> Help me here with this statement, I'm confused:
>
> >It doesn't make much difference whether the night was warm or not. It takes a
> couple of hours for an SCT to adjust to the outdoor temperature once it is
> setup to start delivering it's top quality images.>
>
> I think he is saying that the temperature did not drop and was similar to the
> enviroment where the scope was stored? (in the below statement)? If so, it
> should already be close to thermal equalibrium with the outside air and need
> little if any cooldown. It should be in for all practical purposes, ready to
> go.
That might be true if the outdoor temperature was exactly as the case it came
out, of inside of the house or the car it came out of, and didn't drop
dramatically
as it does when the sun goes down usually, especially if the OTA was subject
to the Sun's rays before it went down as Jay has pointed out. If there was a
difference of a few degrees there will be some adjustment time. Typically
I have found this to be around 2 hours.
Whether it is warm or not makes little difference, it is the difference
of the temperatures between the telescope case environment and the
ambient outdoor temperature that counts and whether the outside
temperature is plummeting or not.
take care,
Rockett Crawford
Jesse Robinson
> Jesse Robinson wrote:
>
> > Rockett Crawford wrote:
> >
> > > Jesse Robinson wrote:
> > >
> > > > Rockett Crawford wrote:
> > > > > IMHO there is no a great deal of difference.
> > > > >
> > > > > I would suggest for anyone that is genuinely interested to go to
> > > > > some star parties and see for themselves.
> > >
> > > > >I have and I saw a tremendous difference. Perhaps it is because I have poor
> > > > quality 8 " SCT Meade and the other individual had a specially good 7 " MCT Meade.
> > >
> > > Or you might have a good SCT and it could be that something was amiss such as
> > > bad collimation, cool down time, or any of a dozen other possibilities as other people
> > > have mentioned. Who knows.
> > >
> > > take care,
> > > Rockett Crawford
> >
> > You are right, there may be another reason for the difference. The SCT is over 10 years
> > old and the MCT is relatively new.
>
> That shouldn't make any difference unless the scope was abused in some way or
> taken apart and put back together improperly, fallen out of collimation, etc...
I have owned the scope since it was new. Never been abused or taken apart. The collimation
look right on to me. The reason for stating the age is that some people on this new group has
stated that the quality control at Meade has improved over the last ten years. Others have
stated otherwise. I have no idea, I have only looked through two new Meades, one the MCT and
the other a small Newtonian.
> > The SCT was set up first and it was a warm night, so cool down can not explain the
> > difference.
>
> It doesn't make much difference whether the night was warm or not. It takes
> a couple of hours for an SCT to adjust to the outdoor temperature once it
> is setup to start delivering it's top quality images.
Good point, what counts is the change in temperature. Richard is correct, I meant that the
temperature did not drop much. Both scopes had been set up for more than two hours. The main
point I was trying to make was that the SCT was set up first. If there was a cool down problem
it would have been with the MCT unless they cool down quicker.
> > I believe the collimation on the SCT is as good as it will get for this
> > scope.
>
> Are you saying that this particular scope is limited in how well it can
> be collimated? If so, it does sound like something is amiss with that
> particular scope.
A defocused star darker shadow is in the center of the lighter circles as the example in my
manual shows.
> > I have looked through a few other scopes and not seen the clarity improvements that I saw
> > in the MCT. The MCT was not the brightest image of Jupiter that I have seen, just the
> > most detailed, but my experience is limited.
>
> Actually, there shouldn't have been much difference in the brilliance of Jupiter
> between a 7 and an 8 inch scope if similar magnifications were used.
Got a chuckle out of you reply. I meant through all the scopes I have looked through, not just
the 7 and 8 inch.
> The best view of Jupiter I ever had was through an 18 inch Dobsonian
> last October on an exceptionally steady night with Jupiter high in the
> sky and late in the night after the sky had thermally stabilized. The view
> through my 11 inch SCT also was extremely detailed and pleasing,
> one of the best I had ever seen also, although not as good as the
> 18 inch.
>
> take care,
> Rockett Crawford
>
> Capella's Observatory
> http://web2.airmail.net/capella
I hope in the future I will be able to view through scopes as fine as you have.
The original poster, Francois, is trying to decide between a 7" MCT Meade and the 8" SCT
Meade. Since I actually compared them side by side at a start party, I thought I would be a
good data point for Francois.
If I had to decide between the 7" and 8", the 7" is well worth the extra money.
jess
Rockett Crawford
Jesse Robinson wrote:
> > The best view of Jupiter I ever had was through an 18 inch Dobsonian
> > last October on an exceptionally steady night with Jupiter high in the
> > sky and late in the night after the sky had thermally stabilized. The view
> > through my 11 inch SCT also was extremely detailed and pleasing,
> > one of the best I had ever seen also, although not as good as the
> > 18 inch.
> I hope in the future I will be able to view through scopes as fine as you have.
>
> The original poster, Francois, is trying to decide between a 7" MCT Meade and the 8" SCT
> Meade. Since I actually compared them side by side at a start party, I thought I would be a
> good data point for Francois.
I have compared them side by side also. The Mak seemed to be a little bit better
for observing planets, but the difference is subtle.
> If I had to decide between the 7" and 8", the 7" is well worth the extra money.
I don't know about "well worth" the extra money. A lot would depend on what
the scope is to be used for. For CCD imaging, the 8 inch SCT would be clearly
better. For deep sky the 8 inch SCT is subtly better, wider fields of view with
higher power eyepieces, particularly with the focal reducer. For planets, the
Mak is subtly better.
For astrophotography, the slightly flatter field of the Mak would be
a plus but it's slow f/ratio would be a bigger minus.
My 2 cents,
Rockett Crawford
Lei Jiang
> A defocused star darker shadow is in the center of the lighter circles as the example in my
> manual shows.
>
That is far from enough. If you ONLY checked this step when you do
collimation, you can't say it is proper collimated.
Probably that's why SCT has bad optical reputation.
Check the following famous page for collimation,
http://perso.club-internet.fr/legault/collim.html
Good luck
lei
Rockett Crawford
Lei Jiang wrote:
Good point. Particularly if the defocused star being checked
is off of center or the seeing is bad during the collimation.
The diffraction rings must also be checked. This seems to
be crucial for fine planetary detail.
This is an excellent web site.
take care,
Rockett Crawford
Jesse Robinson
> >
> > A defocused star darker shadow is in the center of the lighter circles as the example in my
> > manual shows.
> >
>
> That is far from enough. If you ONLY checked this step when you do
> collimation, you can't say it is proper collimated.
> Probably that's why SCT has bad optical reputation.
> Check the following famous page for collimation,
>
> http://perso.club-internet.fr/legault/collim.html
>
> Good luck
>
> lei
My scope does not pass the second step. Tonight I will collimation the scope again.
Great information, thanks
jess
Zeus194340
schmidt verse a 7" mak, if ya look through both side by side there is not
enough difference in deep sky object to make the 8" better and same for
planets, but the 7" can resolve alot more detail, now if you went to 10'
schmidt verse a 7" mak then it would be better to lean twords the 10".
that is my 2 cents worth..............
Zeus194340
from looking through them, not any 2 of the same telescopes is created equall,
much less the difference of the two from different manufacturers. As far as
image being bigger i meant the 8" and 10" have bigger aperture therefor gather
more light. Your experiences may be different, i have been to alot of star
parties throughout the country and have looked through alot of telescopes, i
agree your 11" sct does do very well due to the aperature, i will never debate
the benifit of aperture, but i will debate that a sct is as good as a mak-cass
in optical quality, it is not!
WHALEN44
is not!>
That's right, it may be better, it may be worse. There are many different
designs of MCT out there,, and there are many different levels of quality in
both MCT's and SCT's.
I do think modern MCT designs are better than modern SCT designs, but there are
few out there, and Meade is not one of them.
For instance if Meade took the 7" MCT and blew it up into a 9", I would bet the
Takahashi 9" SCT would out perform it.
There are so many different levels of quality from scope to scope of the same
size, design and brand
that it's hard to make absolute statements about them.
Zeus194340
optically, i know from star parties my 7" (meade) has out performed the meade
8" and celestron 8", maybe i have a exceptional 7", i was not the one who said
mine was better the other owners did.I just enjoy it because it has GOTO
technology along with awsome optics
Zeus194340
views than both of em.......hahahahahha
Rockett Crawford
Zeus194340 wrote:
> If i had a choice of another telescope i would buy..........a 16" dob, better
> views than both of em.......hahahahahha
If it was a good Dob, I agree, absolutely. If I was into observing only,
my preference would be to get the largest good quality Dob I could afford,
something like a large Obsession or a Techtron. Anyone that looks through
a well collimated good quality 18 inch Dob like an Obsession for the first
time will have their idea of what a pleasing image is instantly redefined. :^)
take care,
Rockett Crawford
-----------------------------------
François Duhem
as I'm very interested in viewing planets, I think that the 7" MCT
would be better suited for me than the 8" SCT. But I have seen
another alternative that proposed to me by a local dealer: a
Takahashi CN 212 on a simpler mount than the meade for about
the same price (15% more, so not really the same price !),
which I would use mostly in it's SC
configuration. Do you think that the gain in optical quality would
be noticeable for me, even on the Meade 7" MCT for planetary observation ?
I have to give my answer quickly because I'm not the only person
interested in this scope, the dealer gives me 1 week to decide.
Thank you for your replies,
François.
Jesse Robinson <jess-r...@home.com> a écrit dans le message :
385EA04C...@home.com...
> A defocused star darker shadow is in the center of the lighter circles as
the example in my
> manual shows.
>
> > > I have looked through a few other scopes and not seen the clarity
improvements that I saw
> > > in the MCT. The MCT was not the brightest image of Jupiter that I
have seen, just the
> > > most detailed, but my experience is limited.
> >
> > Actually, there shouldn't have been much difference in the brilliance of
Jupiter
> > between a 7 and an 8 inch scope if similar magnifications were used.
>
> Got a chuckle out of you reply. I meant through all the scopes I have
looked through, not just
> the 7 and 8 inch.
>
> > The best view of Jupiter I ever had was through an 18 inch Dobsonian
> > last October on an exceptionally steady night with Jupiter high in the
> > sky and late in the night after the sky had thermally stabilized. The
view
> > through my 11 inch SCT also was extremely detailed and pleasing,
> > one of the best I had ever seen also, although not as good as the
> > 18 inch.
> >
> > take care,
> > Rockett Crawford
> >
> > Capella's Observatory
> > http://web2.airmail.net/capella
>
> I hope in the future I will be able to view through scopes as fine as you
have.
>
> The original poster, Francois, is trying to decide between a 7" MCT Meade
and the 8" SCT
> Meade. Since I actually compared them side by side at a start party, I
thought I would be a
> good data point for Francois.
> If I had to decide between the 7" and 8", the 7" is well worth the extra
money.
>
> jess
>
Zeus194340
for optical quality. Do you want to do astrophotography, if you do make sure it
comes with a good mount, that is 1 + to the LX-200 has goto and tracks the
objects, simple field de-rotator and ccd and off i go, but optically the tak
is superior