View Full Version : Can't take long exposure photos?

2011-Jun-12, 08:45 PM
So I have an 8 inch celestron schmidt cassegrain telescope sitting in my family room. I bought it back in 1988 or 89. At the time I purchased it, I was told it would be able to take long exposures of deep sky objects, all I would need is to add another motor and a few odds and ends here and there.

Been years since I have messed with it so have mercy on me. I have taken a few pictures with it of Jupiter, the Moon and Saturn, but never got around to getting the other parts I need for longer exposures.

I live in the Seattle area, so not sure if I want to spend a ton of money to try and get it to where I can take deep sky photos. Not really worth the time up here since I get about 4 days a year where clouds don't roll in.

Just more or less curious if anyone know if I would even be able to take them with this thing or not. It's a C8, very basic model with the RA motor in the base, but nothing more. Would I need to buy a completely new mount with all the fancy gadgets for tracking? Since I can't really find a telescope store near me, Im not sure where to start. My time is very limited and the weather isn't very freindly towards would be ameture astronomers here, so I don't even know if it would be worth my time or effort.

Would it be cheaper to just go out and buy a new scope with all the extras added already? Or do you think what I have would be worth just fixing up? Would we be talking hundreds? Thousands? Not talking about camera equipment, just the scope. I can get the CCD and stuff I want later, if I decide to try and get this thing upgraded.

2011-Jun-12, 11:35 PM
There are imagers there in your area. See your astronomy clubs for the hands on help you need.

Sounds like the scope has no slow motion controls or guider port. If so this will make the conversion more complicated. This scope dates back to the day of manual guiding which is ill suited for today's CCD resolution. Especially if the RA motor is AC rather than DC that today's guiders are made for. Still a relay box system with frequency controller (hard to find any more) plus a declination motor would get you up and running along with a guiding camera and off axis guider. Not a trivial expense. If DC motors no frequency controller would be needed cutting costs a bit.

You might want to just use a DSLR mounted atop your scope. This can take some rather good wide field images without the conversion expense. Again see a local club for the hands on help you need. Links to three in your area, there may be more as I only checked very near Seattle.


I should add that a C8 has a rather long focal length, even with a f/6.3 reducer which I forgot to mention. This makes the learning curve very steep. This is one reason I suggested the DSLR atop the tube for wide field work. Gives good results with minimal effort and skill. For imaging through a scope I recommend starting with a scope with say a 500mm focal length. Even small aperture (say 66mm) APO or high quality ED can take spectacular images with a still steep but manageable learning curve. Starting with a C8's focal length is like learning skiing on the experienced skier only slopes. Not as cheap as modifying the C8 but more likely to give reasonable results. Still expect a very steep learning curve not only for the imaging part but also for the imaging processing part. Software for that isn't cheap either! I've been climbing the learning curve now for 50 years and am still to see the top. I glimpse it now and then then it falls back into the fog of ignorance.

Hornblower is right about the equipment side. Good equipment makes it more enjoyable but you have to know what you're doing. Years ago Richard Berry, then editor of Astronomy Magazine wrote an editorial about "90 Day Wonders" who threw money at the best equipment only to discover that without the knowledge to use it, it is totally useless and are gone in 90 days. You have to start at the bottom and work up. Hence my suggestion for starting with a camera atop the C8. Then move to a short focal length APO on a modern mount etc.


2011-Jun-12, 11:35 PM
I would recommend finding a club in your region where you could pick some brains. There you may find some good advice on mounts and guiding accessories, as well as observer experience and wisdom. I do not think it is much if any exaggeration to say that good deep sky work is about 1% good equipment and 99% skill and experience on the part of the operator.

Edited: I see Rick beat me to it in posting. He is a great resourse.

2011-Jun-13, 08:17 AM
Okay, thank you Rickj, and Hornblower, I will try and look into a club I can go pick some brains over. sounds o me that it would be easier to just start from scratch, but we'll see. Makes me sick, when I first got this thing I knew a lot more than I do now about it. Just been too long since I used it much, but lately I have been getting the bug to get back into it. Now I find this site, and see all these beautiful pictures you guys take, and it really maes me want to try it again. My pitiful little jupiter pictures are quite pathetic compared to the ones I've seen here.

Oh well. Thanks for all the info, I'll post here if I find a good club that will work with my work schedule.