Sunspot Group AR 1236 in CaK

 group1236-jun20-1

Image Data

Telescope: 90mm Synta Skywatcher f/10 Refractor on Celestron CG5 German Equatorial
Focal Length: 900mm
Accessories: Ca II K Interference Filter (approx 2.2nm bandpass), Baader Calcium K-Line Filter
Camera: Imaging Source DMK72AUC02
Frames Stacked: 800
Exposure Date: 20th June 2011
Location: Prague, Czech Republic
Software Used: Avistack, Registax, Photoshop