Large Dob (20"+) For Astrophotography?

Ive had a Nexstar11 for now 6 months..and have done visual observing up until now and plan on getting into AP, starting out with planetary webcam imaging first to test the waters. I live near boca raton, florida..so the light pollution is pretty crappy, but better than the cities..

Having a Nexstar 8se in the past (and a 90mm Meade ETX prior)..ive steadily went up in aperture over the years and think im afflicted with the aperture fever thing...i love searching for those faint fuzzies and especially the really faint ones..when I find em I just feel accomplished..hell, I might want to do some comet/asteroid/NEO/supernova research in the future since I'm still pretty young (in my 20s) . Is it possible to use a large dob for AP work, with the servocat/argo navis attached? (id assume you'd also need a field de-rotator since you cant put it on an EQ mount, unless you use an eq platform).

Or...is the big dob a thing mostly just for visual work for guys who live in the countryside...or have a trailer where they can transport it? Im not experienced AP wise..so forgive my language barrier..but am eager to learn...

Thanks

Hi Mike. I'll take a shot at answering this question. I have only seen a few imagers who use large dobs... Al Kelly is the main one who comes to mind. The problems with big dobs are pretty tough. First, you would be working with a long focal length, so any error in tracking is magnified. Second, the things are like a big sail in the wind. Even the slightest breeze would have them shaking like a leaf. Third, the field rotation is another problem, but it can be dealt with using a derotator, assuming all the other problems were solved. I think that most imagers using a big dob have them mounted on an eq platform, but most of those platforms are not really smooth. I have seen some wonderful images taken with big dobs on split ring mounts. If you decide to get serious about spending cash, I know a guy who builds world class split ring mounts for dobs. He mostly uses his for scientific work, but occasionally takes a break and takes "pretty pictures" (as he calls them). Each of his mounts is custom made... nothing is mass produced. If you are interested, send me a private message and I can send you contact info. I think his mounts probably start at about the cost of a Paramount, and go up from there. That is my 2-cents worth.
Cheers,
Tyler

I think most people use a EQ platform who are imaging with Dobsonians...

http://www.cosmicimpressions.com/galaxies.html

Like any photography, one needs to match the lens to the target. Given the relative importance of the mount and the telescope in astrophotography, a Dob is probably not the ideal choice for most targets.

Jon