Sunday, 16 September 2018

Comet 21P/Giacobini-Zinner

Comet 21P/Giacobini-Zinner was imaged using AstroDMx Capture for Linux with a ZWO ASI178MC camera at the prime focus of a Bresser Messier-AR-102-AS ED refractor, mounted on an iOptron Cube Pro AZ, GOTO mount. 10s, 16 bit TIFFs were collected with matching dark frames. The images were stacked and dark frame corrected in Deep Sky Stacker running in Wine. The image was post processed in the Gimp 2.10.

Comet 21P/Giacobini-Zinner

Alignment was difficult from the site chosen, and tracking was not perfect. However, about a third of the images captured were good enough to stack. The exposures were of limited duration due to tracking issues. Nevertheless, the comet tail and star colours showed up quite well. Focus was a little soft and is not as easy to achieve as with a dual speed focuser.

The ZWO ASI178MC camera

This camera has a 14 bit ADC so it is much less likely to saturate. AstroDMx Capture for Linux auto detects the ADC bit depth and so correctly places the data into either the bottom or the top bits (User defined) of a 16 bit container.