Hi Dave
The ‘scope is a Tak Mewlon 180mm F12, a Dall-Kirkham Cassegrain design. The native focal length is 2160mm and I am experimenting with the Tak x1.6 Extender (efl of 3450mm at F19.2) and a WO x2.5 Barlow (efl of 5400mm at F30) to optimize the image scale/exposure combination.
So far, the Tak 1.6 Extender and 30 sec exposures seems the best combo, producing tighter stars whereas 30 secs at an efl of 5400mm smears the light, not unexpectedly!
The SBIG ST7 CCD camera has a 2” nose piece which sides into the x1.6 Extender or WO x2.5 Barlow. The assembly then slides into a Moonlite motorized focuser.
Cheers
Dennis
PS – Here is a link to
Tak Europe for details on the M180.