M15 Globular Cluster
Date: 8 August 2004
Telescope: Celestron 11” SCT with stabilized mirror on Gemini G-41 mount
Guiding: ST-4 Autoguider with Celestron C80, 80mm F11 refractor on side-by-side plate.
Camera: Genesis KAF-1602E with Astronomik FR-4 filterwheel with 34mm LRGB filters, Meade 0.63x reducer in Ted Argos adapter.
Location: Tai Mei Tuk, Hong Kong
Exposure: Luminance filter: unbinned 12 x 4mins
Red filter: 2x2 binned 5 x 2mins
Green filter: 2x2 binned 5 x 2mins
Blue filter: 2x2 binned 10 x 4mins
Software: Image acquisition by Astroart, calibration and auto-alignment also in Astroart, sigma-combined by Sigma, color combine and DDP in MaximDL, blooming removal (by rubber stamp) and final brightness adjustment in Photoshop.
Comment: The reducer in Ted Argos adapter was set to the same length as the Celestron 55mm SCT-T adapter, there was coma at corners.