User:Searly/Astronomy

Saturn eclipsing the sun

Astrophotography

As with any optical equipment I get my hands on, the primary use for my telescope platform is astrophotography.

Astronomy Equipment

Astrophotography platform

My optical platform is a Celestron C8 optical tube on a Losmandy GM-8 mount. The rig is capable of locking onto and tracking a star to provide multi-hour exposures.

Mount

The Losmandy GM-8 is a high quality German Equatorial style telescope mount with a 30lb load capacity. It has stepper motor drives on both axis, and accepts ST-4 style autoguider inputs.

Optics

The C8 optical tube is a Schmidt-Cassegrain design with an 8-inch (200mm) diameter primary mirror. It's native specs are 2000mm focal length at f/10, and 1260mm at f/6.3 with the addition of a focal reducer/field flattener. The C8 is used for high magnification deep-sky work.

For wide-field work, I also have a set of Canon FD manual focus prime camera lenses covering the 28mm-200mm range that can attach to the CCD camera, and Canon EF lenses for the EOS 20D.

At some point I hope to acquire a f/5 refractor OTA in the 60mm-80mm aperture range, likely an SD Achromat or inexpensive Apochromat. This would fill the gap between the C8 and the camera lenses for medium-field work.

Cameras

My long exposure camera is a Starlight Xpress MX7C thermoelectrically cooled color CCD camera. This camera has a simultaneous track and accumulate capability, so that it can both image and guide the telescope at the same time. The camera package includes an ST-4 autoguider output to send tracking corrections to the telescope mount.

I can also use my Canon EOS 20D camera for either prime focus or piggyback photography. The 20D is known to have sufficiently low noise levels to get acceptable images without cooling.

Digital Imaging Software