The Horsehead nebula.
Evening of 16 February 2002, Horse Head nebula in Orion. 9 images each selfguided for 10 minutes through the SBIG CFW-8 red filter, binning 1x1, temperature -20°C.
As you can see, the Sigma 400 f/5.6 APO has a problem with internal reflections on bright stars.
I also made a set of 2x2 binned RGB images, R = 20 m, G = 20 m, B = 40 m and combined this to a RRGB 90:20:20:40.
22/11/1998. Lichtenknecker Optics Flat Field Camera 190/200/760. SBIG ST-7 30 m selfguided exposure.