Sunday, 20 October 2019

Python and the Moon

A motor-focuser-adapted Bresser Messier AR 102xs f/4.5 ED refractor was placed on a Celestron AVx GOTO mount, and a DFK 21AU04.AS camera fitted with a 2.5x Barlow was placed at the prime focus. 1500-frame AVIs were captured of ten overlapping regions, to cover the terminator of the 64.2% waning Moon. A short Python, with OpenCV3, program running in the Thonny IDE, on an Ubuntu 18.04 laptop, was used to control the camera and capture the AVIs captured using a lossless HFYU Hufman compression codec. VirtualDub was used to decompress and re-save the AVIs. The best 80% of the frames (1200) were stacked in Autostakkert!, precisely cropped to 640 x 480 in the Gimp 2.10, stitched in Microsoft ice and Post processed in the Gimp.

Screenshot with the preview flipped into the correct orientation and enlarged to facilitate focusing

Screenshot of the python program capturing the 1500-frame AVI

An individual pane of the Clavius region

Ten-pane mosaic of the terminator of the 64.2% waning Moon

Full size

Python with OpenCV is a powerful system for machine vision, and can be used to build capture systems. The code is not presented here as it is a work in progress, and is part of another project. Eventually, it is likely that the code will be presented here some time in the future.