Astrophotography telescope for amateur photographer

Hello,

I am a serious amateur nature photographer with a long interest in astronomy
and star gazing. I have done some fixed camera astrophotography, as well as
plenty of naked eye, binocular, and 60mm refractor star gazing.

I'm looking for a telescope and mount for astrophotography. My priorities
are on getting a quality German style EQ mount with a clock drive - which I
would probably sometimes use with just a camera and telephoto lens (without
the telescope). I will settle for a lesser telescope if I have to choose
between the mount and the scope, and I have a couple of sturdy tripods
already so I don't want another tripod with the telescope. Also, I
definitely don't want to put any money into a "GoTo" capability, I'd rather
find the objects myself. I'd love to come in well under $1000, but would
consider spending up to that.

Here are my questions:

- Is it possible (it must be) to get a scope and mount separately, and
without a tripod? I don't get that impression from the Celestron, Meade and
other websites, they seem to want to bundle everything together.

- My research tells me that a Schmidt-Cassegrain or Maksutov-Cassegrain are
the most popular choices for astrophotography, but of course a "fast" scope
is also desirable for astrophotography. Unfortunately I haven't found any
catadioptrics with short focal lengths (fast focal ratios). Am I missing
something?

- Assuming the SCT or Mak-Cass doesn't work out, how about a short focal
length f/5 Newtonian such as the Celestron C6-N or equivalent? My concerns
are 1) I've read that on some Newtonians the secondary mirror has to be
moved in order to achieve prime focus astrophotography. Are there any
Newtonians that would not require this modification? 2) I'm also worried
about hanging a metal chassis manual camera body (20 oz) off the front end
of a Newtonian as far as vibration and distortion of the telescope optics
are concerned. Are my concerns valid, or is it no worse than hanging the
camera off the back end of a catadioptric?

- How about a fast refractor? Any decent ones for prime focus
astrophotography in my price range?

I really appreciate any advice offered as I'm sure some of these inquiries
get a little old.

Thanks.

Bruce

Hi Bruce,

- How about a fast refractor? Any decent ones for prime focus
astrophotography in my price range?

You might check out http://www.light-to-dark.com/ for some good work with a
small, fast, affordable Stellarvue refractor. Vic Maris, the owner of
Stellarvue, cautions prospective users of his scopes that for serious long
exposure work you'll need at least a $1000 mount.

Gary Fuchs

The Celestron catalog does have stand-alone OTAs as I recall (cannot
find it just now).

Thanks, "OTA" is the terminology I needed, no wonder I couldn't find
anything.

You can add a reducer/corrector ($130 or so) to the rear of the SCT to
get to f/6.3. I believe there is also an f/3.? model. So that should
not be a problem.

I guess you're right. I thought it would be better to not have to use an
additional piece of optics, but here's what the Celestron website says:

Celestron doesn't offer a f/6.3 Schmidt-Cassegrain telescope, because the
design is impractical, with a large central obstruction, and resulting loss
in contrast. This, added to the inability to utilize longer focal ratios for
certain objects, led Celestron to design the four-element, fully multicoated
f/6.3 Reducer/Corrector. Results are amazing both visually and
photographically.

Plus the only fast SCTs I've found have been high end and too expensive for
my budget.

Actually I've done some thinking and I realize I'm not THAT interested in
astrophotography through a telescope. I like having Earth in the
foreground, which means fairly wide angle stuff, so my camera lenses should
pretty much cover me. What I really want is a good equatorial mount so I
have the option of "freezing" the stars and letting the terrestrial
foreground blur, but I would also like to have the ability to at least
dabble in through-the-telescope-astrophotography. I think my longest
lens/camera combination is about 5lbs, does anyone know if something like
Celestron's CG-5 with a standard right ascension drive would provide decent
results for exposures up to 10 minutes or so with a 300mm lens? And how
about the CG-3 to bring along on backpacking trips for use with shorter
lenses?

Also of course I would like a decent telescope for visual observation. I'm
getting interested in the Celestron C5-S, it comes with the CG-5 mount
(which includes a tripod that I would probably try to sell off.). Or if the
CG-5 seems like an inadequate mount, I would consider getting the C5 OTA (or
maybe even the spotting scope) and a seperate mount. Anyone know of any
GEMs positioned between the CG-5 (at ~$300) and something from Vixen or
Astro Physics which look like they cost over $1000?

Thanks again.

Bruce

Thanks,

I'll see if I can get my hands on the August S&T.

Bruce

"Mike Wagenbach" wrote in message
om...
"brulu" wrote in message
...
Also of course I would like a decent telescope for visual observation.
I'm
getting interested in the Celestron C5-S, it comes with the CG-5 mount
(which includes a tripod that I would probably try to sell off.). Or if
the
CG-5 seems like an inadequate mount, I would consider getting the C5 OTA
(or
maybe even the spotting scope) and a seperate mount.

If you like, the same mount is available through Orion as the
SkyViewPro, either alone or in packages. As far as I know, they don't
sell the mount head separately from the tripod.

The current issue of Sky and Telescope has a review of this mount
bundled with a 6" Newtonian, and has a sidebar about tweaking the
mount for imaging. As far as I can remember, they don't show any
attempts at actually imaging with it, however.

This is a pretty new mount package, so it *might* have altered the
conventional wisdom about cost of imaging mounts. I have one, but
only use it visually, so I can't comment. Visually, it is pretty
nice. Polar scope and drives are extra cost, but pretty cheap.

Apparently refractors are usually used as guidescopes. I've read that
the focusers on the Chinese refrators are too flexy for guiding, so
you'll probably want to get something from someone else. If you only
want to do piggyback conventional lens photography, you might
investigate whether there are rings to fit the 90 mm Mak-Cass and try
that as a guidescope, to keep weight, length and cost down and focal
length up. The obvious concern would be mirror flop during an
exposure. Thanks perhaps to Synta's infamous glue/grease in the
focuser, my 127 mm mak shows little image shift, so this might not be
a problem.

If you do want to try photos through the scope, the Celestron SCT
would be a better choice.