Sunday, December 25, 2011

Yet Another Telescope

Telescope #5 joins the fleet.

For a while I've been looking for a better way to do wide-field astrophotography. I started by trying to use my ST-80 in this role. Its focuser (a replacement GSO model) just wasn't up to carrying the weight of my SBIG ST-8300M, and its optical quality was not very good. As I've mentioned in past posts, I looked at getting an adapter that would let me mount Canon lenses on the SBIG. That seemed a little too single-purpose, given the cost ($280).

Last night (Christmas Eve) someone put an AT72ED up for sale on Cloudy Nights, and I jumped on it. At $285 + shipping I hope it will be the most flexible solution.  It's a bit faster than my TV102 (f/6 vs. f/7)and much shorter in FL (432 vs. 700 mm). Its field of view is a spacious by 2.4 by 1.8 degrees. Questions remain: How robust is the focuser? How well will the Orion field flattener work with it? Commenters have noted that its focuser is much better than the standard 2" focuser by GSO. I've never read about someone pairing the Orion FF with this scope (most people use the AT or WO FF) so I'll have to find out for myself.

The seller is someone who just upgraded to an AT111 and apparently decided he could do without the 72. As for me, this will probably take the place of my ST80 as my travel scope. The ST80 now can retire to its role as Autoguider, for which it is well suited.

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