Monday, December 19, 2011

Next Telescope?

I enjoy wide field imaging, and it's easier for someone like me who is learning astrophotography. Tracking errors are less evident, and the hardware to image is smaller and less heavy.  The mount has an easier time carrying the load, and the smaller profile means wind presents less of a problem.

What should it be? I had my sights set on an AT65EDQ, a triplet with built-in field flattener:
Astro-Tech AT65EDQ
Typical Moonlight Focuser
But it seems to be no longer for sale, and if it comes back it will probably have a long period on back order.  The AT65's focuser is probably not capable of carrying my ST-8300M and filter wheel. So it almost demands a focuser upgrade, and that is expensive: Something like $400: Above is a high-quality Moonlight focuser that would be perfect.

When all is said and done, it's nearly $1,000.

Another option is to use the two Canon lenses I use with my XTi. This requires an SBIG adapter that costs $280:
SBIG EOS adapter for ST-8300 w/filter wheel
This covers the focal length range from 17 to 70 mm, which is shorter than I want. If one of these were to pop up for sale used, I'd probably go for it for full constellation imaging. Moog adapters used to be available for this purpose, but their business has been scaled back and because of the filter wheel, this would require custom work on their part.

I already have a field flattener for my ST-80, so any short-focus telescope is basically ready for imaging. What I want is something with a better than average 2" dual-speed focuser and focal length less than 430 mm. The model I've read about that seems to have the best focuser is the AT72ED; new this is $380 and used usually round $250-$300. Another scope is the Stellarvue SV70ED, which also gets very good reviews.

Astro-Tech AT72ED
Stellarvue SV70ED
I've put in a "wanted" post on my club's web site, and I'm watching Cloudy Nights and Astromart for used scopes and SBIG-Canon lens adapters.  I wonder how long it will take for something to show up.

No comments:

Post a Comment