700-800mm Focal Length Refractor for AP
Posted 12 February 2013 - 09:35 AM
I have been weighing my options for an 700-800mm focal length refractor for AP. I currently have an AT65edq which I really like, so basically I want to double the focal length for smaller objects. I have an AT6RC that I am selling to help fund this, I really do like the plug and play ability of the refractor, so I am leaning that way. I would really like to keep the budget below $1500, I currently have the AT2FF field flattener so I may not need another FF. The scope will be mounted on a Mach 1 and the camera is a QHY8. If I can find a good deal in this focal range I will have a focal length assortment if 420, 700-800, 1600, and 2500mm which should cover everything I want to shoot.
Thanks for the help,
Posted 12 February 2013 - 03:02 PM
There are also a lot of 100mm f8 to f9 refractors out there. I used an Orion 100ED for a long time. Worked fine but the focuser needed help. I also have a QHY8 and that, plus OAG and guide camera, was too much for the stock focuser and even a William Optics.
.. although with a Mach1 (I got one recently) the need for OAG is much diminished if not eliminated. A simple finder guider works great since the periodic error is so small now..
If you can get one of the rare Stellarvue 100mm f8 Lomo optics with Feathertouch focuser, that would be right where you want to be. Can't underestimate the value of the focuser. And the SV 100/8 Lomo usually goes for $1100 to $1200. It is a bit slow at f/8 that's the only drawback.
If you want 700-800mm and faster, it's hard to beat the ES127 plus a reducer which would take it down to 762mm f6.
Posted 12 February 2013 - 05:04 PM
Posted 12 February 2013 - 07:28 PM
Posted 14 February 2013 - 11:55 AM
Posted 14 February 2013 - 05:53 PM
Great choice. I do the same with my older AT111 and the AT65. I have had excellent results with both scopes!
Posted 14 February 2013 - 07:15 PM