The complete field setup, from the concrete pier and absolute-encoder mount to cooled cameras, focusers, dew control and the eyepiece case.
The mount is the most important part of an imaging setup. Accurate go-to and tracking matter enormously at long focal lengths and over long exposures, and carrying capacity comes at a price.
Absolute encoders · concrete pier · high-precision tracking
The GM2000 HPS is a beast of a mount. Its absolute encoders know the position of the motors to high accuracy, giving it excellent go-to and tracking performance.
I bought it second-hand from a seller in Italy through Astromart. It was still expensive, but the mount is the most critical piece of equipment for serious imaging. At Pinnacle Hill it is permanently aligned on a home-made concrete pier.
Portable equatorial mount · tripod based
Before the GM2000 I used a Celestron CGEM DX. Its accuracy is lower, but it remains useful when another telescope is needed for visiting groups such as local Scouts.
Because it has its own tripod, it also gives the observatory a portable mount that can be moved and set up away from the pier.
The proper name is optical tube assembly, although most people simply call it the scope. Two very different designs cover narrow, high-magnification targets and wider deep-sky fields.
279.4 mm aperture · f/10, f/7 and f/2
The main scope uses Schmidt–Cassegrain optics. It is a versatile instrument capable of imaging at f/10, f/7 and f/2 with the right adaptors, while its native flat field is well suited to astrophotography.
I flocked the inside of the tube with super-black material to reduce reflections, and added electronic focusers and dew heaters for humid Bombay Hills nights.
80 mm apochromatic triplet · 480 mm at f/5.6
The carbon-fibre Orion is an 80 mm apochromatic triplet. It does not have the aperture of the EdgeHD, but produces sharp, high-contrast images and provides the wider field needed to frame larger deep-sky objects.
A Tele Vue reducer and flattener brings it to f/5.6. The scope sits above the EdgeHD, well within the GM2000 mount’s carrying capacity.
Astronomy cameras attach directly to the telescope—the telescope becomes the lens. Their low-noise sensors are often thermoelectrically cooled for long exposures.
16 MP · cooled monochrome · deep-sky imaging
The ASI1600MM Pro is the main monochrome camera. A seven-position electronic filter wheel captures red, green, blue and additional filtered data that is combined into the final image.
Its regulated cooling can lower the sensor 40–45°C below ambient temperature, helping control noise during long deep-sky exposures.
11.7 MP · cooled colour · up to 19 fps
The ASI294MC Pro is the main colour camera and a strong all-rounder for deep-sky and planetary work. It is also the camera used with the EdgeHD in HyperStar f/2 mode, where there is no room for a filter wheel.
A filter slider accepts an IR-cut or light-pollution filter. At full resolution the camera can capture at around 19 frames per second.
Monochrome · lunar, solar and guiding
The ASI174MM is used for the Sun and Moon and also works well as a guide camera. Those short-exposure roles do not require thermoelectric cooling.
Focusing, dew control, target finding and calibration sit around the main imaging train and make repeatable automated sessions possible.
Electronic fine focus
The MoonLite attaches to the rear of the optical tube and changes the distance between the camera or eyepiece and the telescope. It can be controlled by hand or by the workstation for automatic focusing.
Wireless coarse focus control
The wireless MicroTouch drives the telescope’s native focus control and handles coarse adjustments. It can also be controlled from the computer, although I normally use its hand controller.
Dual-channel heater control
Heater straps keep dew away from the EdgeHD and Orion optics. The dual-channel controller allows each strap to be adjusted independently as the humidity changes.
Visual finder · calibration light source
The Telrad projects illuminated half-degree, two-degree and four-degree bullseye circles for a quick visual check of where the telescope is pointing.
A Spike-a Flat Fielder produces an evenly illuminated surface for flat frames, which are used to calibrate dust, vignetting and uneven field illumination out of captured data.
Astrophotography is only part of the hobby. A range of eyepieces keeps the observatory ready for visual sessions and visitors.