(12 December 2008)
The Virgil Observatory is home to a 12-inch Meade f/10 SCT classic
mounted on a home-made, fixed-angle wedge and SkyShed pier. The pier is
bolted to a 12-foot 12-1/2 inch diameter footing of 2000 pounds of
concrete. I use ACP Observatory Control with the
I have an SBIG ST-7XME, a camera with a CCD detector similar to my
old Pictor 416XTE, but with a completely different electronic
interface. This camera uses a USB 2.0 interface that is both more
reliable and provides significantly faster downloads. I use MaxIm DL/CCD
to control the camera.
Currently I use an f/6.3 focal reducer and a spacer to get a focal length reduction to
about 55% (1630 - 1635 mm), with a resulting image scale of 1.14
arcsec per pixel and a field of view of 15' x 10'. The effective
reduction depends on the both the distance of the reducer from the
secondary mirror and the distance of the reducer to the CCD chip
itself. Changes in ambient temperature change the effective
The following equipment is mounted on the telescope, in order from the telescope tailpiece:
a) The f/6.3 focal reducer. The focal reducer is mounted inside the TCF-S focusing sleeve
in an Agos adapter.
b) Optec TCF-S focuser (with digital readout), using FocusMax to automatically focus.
c) A very short T-thread spacer. (An AO-8 could go here instead.)
d) SBIG CFW-8A color filter wheel, with Hα, V, R, I and Clear filters.
e) SBIG ST-7XME CCD camera, cooled typically to -35C to -25C in the winter
and -15C or -10C in summer, but not water cooled.
With this configuration, the OTA will not swing through the forks, so I'm limited to observing
objects that are south of declination 69°N.
The roof, an AstroHaven Enterprises 7-foot diameter clamshell, opens and closes
takes little effort to move the four shutter segments up or down. Once it's moving, it
takes only about five seconds to fully open. The clams open to the north and south. Each shutter can be opened or closed independently. An ASCOM Astrohaven driver links the dome
shutter control mechanisms to the computer.