Questar and astrophotography
Laurence H. Field
While on the subject of Questar performance, has anyone tried out the
Questar Starguide off-axis tracker? It has vignetting in the Q3.5 so
severe that the central crosshairs box on my 12mm Univ Optics Plossl
illuminated reticle EP is partially occluded. One can hardly guide on
stars when the upper 45-50% of the field is vignetted! With Questar's
13mm EP, the vignetting knocks about the upper 30% of the FOV, but of
course there's no illuminated reticle for guiding.
Another problem: if the Starguide is put on the Q7, it positions the
camera so far back that the focus shaft can't provide enough backfocus
to give a focussed image on the film plane. I've tried repositioning the
focus knob, but it doesn't help. The focus shaft is actually not
threaded enough to provide the large back focus seen on the Q3.5. THis
eliminates prime focus photography on the Q7 using the
Starguide.....another disappointment with Questar. Has anyone overcome
this on a Q7?
Larry
Clive Gibbons
In article <3589C3...@csc.canterbury.ac.nz>,
Laurence H. Field <zoo...@csc.canterbury.ac.nz> wrote:
>While on the subject of Questar performance, has anyone tried out the
>Questar Starguide off-axis tracker? It has vignetting in the Q3.5 so
>severe that the central crosshairs box on my 12mm Univ Optics Plossl
>illuminated reticle EP is partially occluded. One can hardly guide on
>stars when the upper 45-50% of the field is vignetted! With Questar's
>13mm EP, the vignetting knocks about the upper 30% of the FOV, but of
>course there's no illuminated reticle for guiding.
Mr. Hubert Entrop was one of the shining examples of what deepsky
photography could be accomplished with the Q3.5 and Q7. He used the
Starguide and Powerguide, with excellent results. Check out some back
issues (especially from the '70s and '80s) of Sky and Telescope. The
Questar ads often displayed examples of his work.
That being said, I personally don't consider the Q3.5 a great candidate
for deepsky shooting. It's baffle system does a great job of cutting down
stray light, but does vignette quite a bit and would make off-axis guiding
difficult. OTOH, it's been my personal experience that the Q3.5 can take
very sharp lunar and planetary photos. I suggest you further explore that
avenue, if you wish to reduce your frustration level! ;)
BTW Larry, do you enjoy *anything* about Questar telescopes? You wouldn't
happen to be related to Jay Freeman, by any chance?? :)
Also, if you'd like to part with either or both of those disappointing
Qs, I'd be happy to safely dispose of them for *no* charge
(I'd even pay for the shipping!)... <g>
Best wishes,
--
Clive Gibbons
Technician, McMaster University,
School of Geography and Geology.
Laurence H. Field
Clive:
Sorry to sound like sour grapes. The mechanical construction and overall
design of the Questars are superb. I expected the optics to be what was
described in all the old S&T Questar ads, hence I naively jumped at the
offer to buy a used one from Vernon scopes, via a contact in the US,
without any current bkgd knowledge such as I'm rapidly learning. I had
no knowledge of star testing etc, and bought all the pricey Questar
photographic accessories with high optimism based upon the "best in the
world" guff in the ads. It was only after looking through other scopes
and coming across Alan McRoberts article on star testing (S&T Mar 95)
that I began to get supspicious, and then disappointed. I'm thinking
that I need to look through a recent Q3.5 to change my impressions. So
if anyone on this net is coming down to New Zealand with their Questar,
please look me up and lets compare!
I'll reserve comments about the Starguide until I dig into the Questar
mailing list archives, but with the price far above Lumicon guiders I
expected good performance. Wouldn't you? Have you tried one out?
Anyway I'll keep in mind your offer! Thanks.
Larry
Fred & Julie Burger
Hi Larry,
If it counts for anything, I own a 1962 Standard Questar and have
found it to have extremely high optical quality. I have owned other
telescopes in the past (including the much touted Zeiss APQ), but the
Questar is still my favorite. So much so, that I recently sold the APQ
and sent my Questar in to be serviced and to have the internal
Powerguide installed (Thank you for your help Stew!)
Please give these fine instruments a chance to work at their
best. Try contacting Questar about having at least the 3.5" serviced.
When working at their peak, these are splendid instruments that never
cease to amaze and impress me.
Best Wishes,
Julie :-)
AndersonRM
In article <358d63a...@news.nas.com>, f...@sos.net (Fred & Julie Burger)
writes:
> I have owned other
>telescopes in the past (including the much touted Zeiss APQ), but the
>Questar is still my favorite. So much so, that I recently sold the APQ
>and sent my Questar in to be serviced and to have the internal
>Powerguide installed (Thank you for your help Stew!)
What was the chief reason you sold the APQ?
-Rich
Clive Gibbons
In article <358CB2...@csc.canterbury.ac.nz>,
Laurence H. Field <zoo...@csc.canterbury.ac.nz> wrote:
>Sorry to sound like sour grapes. The mechanical construction and overall
>design of the Questars are superb. I expected the optics to be what was
>described in all the old S&T Questar ads, hence I naively jumped at the
>offer to buy a used one from Vernon scopes, via a contact in the US,
>without any current bkgd knowledge such as I'm rapidly learning. I had
>no knowledge of star testing etc, and bought all the pricey Questar
>photographic accessories with high optimism based upon the "best in the
>world" guff in the ads.
Understood, Larry.
I had suspected that your comments about those Questars might have been
motivated by some kind of grudge or anti-Q bias. It's now obvious to
me that this isn't the case. Please accept my apologies!
All I can add is that the Q advertising might make it sound that
performing certain tasks with the scope (like deepsky photography) is
easier than it actually turns out to be. The build quality and materials
of the accessories are very high, and they're not cheap (due to this, and
the limited volume of production), but the end results also depend on the
experience and perserverence (stubborness? <g>) of the user.
>
>I'll reserve comments about the Starguide until I dig into the Questar
>mailing list archives, but with the price far above Lumicon guiders I
>expected good performance. Wouldn't you? Have you tried one out?
Nope, I haven't tried a Starguide. I'm sure it *can* be used to take
long-exposure shots through a Q, but I wouldn't have the patience to set
things up and "go for it". It's my suspicion that most Questar users would
find using such an accessory to be a rather frustrating experience... I
know that using an off-axis guider on my ol' C-8 often was! ;)
>
>Anyway I'll keep in mind your offer! Thanks.
>
>Larry
Cheers and thanks for sharing your Q experiences!
David Nakamoto
HI Clive!
Clive Gibbons wrote:(Snip!)
> All I can add is that the Q advertising might make it sound that
> performing certain tasks with the scope (like deepsky photography) is
> easier than it actually turns out to be. The build quality and
> materials
> of the accessories are very high, and they're not cheap (due to this,
> and
> the limited volume of production), but the end results also depend on
> the
> experience and perserverence (stubborness? <g>) of the user.
This is very, very true. As a personal example that just happened to
me, afteralmost two years of frustration, I sold my Meade 216XT to a
friend of mine.
I'm still a neophyte astrophotographer, and he's more experienced. The
end
result was that his first attempts were a lot better than mine.
Astrophotography is not, NOT easy for a total beginner, especially when
you
need to work with small CCDs and large apparent magnifications. It's no
wonder that the early good results by amateur imagers were done by
people
with a lot of astrophotography experience already.
But those experienced people had to get their experience from somewhere,
and that somewhere is lots of time spent at the scope.
Since El Nino seems to whip out every stinking opportunity I try to
arrange
to get to my favorite dark site on New Moon weekends, I'm going to try
and get there EVERY weekend for a while and take my chances. At least
that way I'll get more experience time with my equipment, most of which
is
now new.
Clear and Steady Nights!
Fred & Julie Burger
Rich, as I said in my post, I sold the APQ because the Questar was
my favorite instrument to observe with. I found that I used the
Questar far more than any of my other telescopes and I decided to sell
the APQ and invest in something more useful like the Powerguide for
the Questar.
To be completely honest, there was one other factor influencing my
decision to sell the APQ and that is the fact that Astro-Physics will
be introducing new telescopes soon and I would like to buy one. The
one thing that is more desirable (to me) than a Zeiss is an
Astro-Physics. :-)
Best Wishes,
Julie :-)
f...@sos.net
Wavefront Web Pages - A web site for Maksutov users
http://www.sos.net/~fjb/Q1.htm
Peter Bealo
> To be completely honest, there was one other factor influencing my
>decision to sell the APQ and that is the fact that Astro-Physics will
>be introducing new telescopes soon and I would like to buy one. The
>one thing that is more desirable (to me) than a Zeiss is an
>Astro-Physics. :-)
> Best Wishes,
> Julie :-)
Julie,
what new scopes????
Peter Bealo
Fred & Julie Burger
Hi Peter,
The Maks that Roland keeps teasing us with of course! :-) That's
not to mention the splendid little 90mm F/5 EDL prototype that AP has
been bringing to star parties too (I have a picture of the EDL on my
web site). I just wish that they would make a little more information
available.
Best Wishes,
Julie :-)