M1.
An image of M1 taken on 30 December 2009 with my Vixen VMC260L + Vixen reducer (f/7.5) + SBIG STL-4020 with Baader RGB filters.
The G and B frames have 6x5m while the R image has 6x10m. I should have kept the R exposures the same as the G & B as it seems the exposure ratio for the Baader RGB filters with the STL-4020 is near 1:1:1. Also during the blue exposures, the sky transparancy decreased as clouds drifted in. So I had quite some trouble to get the colour more or less "right"! Below is a second version, the first version had a wrong color balance and the one below is probably not quite right either, I had a lot of difficulty to arrive at this image, guess it needs another redo at the telescope first....
This image was made on 21-22 December 2000 in the focus of my Opticon 250 mm f/15 SCT with my ST-8 (binned 2x2 and cooled to -20°C) and CFW8.
I made 6 images of 10 m integration each, using the red filter in the CFW8 - in addition, one 10 m green image and two 10 m blue images were made. All images were added together to make up the luminance image. The two blue images were added together; with the green and one of the 6 single red images the LRGB image was made. All individual images were of course dark subtracted and flatfielded. There seems to be a problem with the blue images (note the "blue points ?") that I cannot correct. Guiding was with the ST-8 SelfGuiding function. The IP programs I used were AstroArt and Photoshop.
This image was made on 29 December 1999 and shows the full field of M1 with the same instruments as described below. This is a 10 m selfguided exposure at -15° C. The image was contrast stretched, log scaled and sharpened in CCDOPS (MS DOS).
M1, 20/11/1998. One of my first deep-sky pictures made with the ST-7a. 190/200/760 FFC, 30 m selfguided integration at -20° C and 9 micron pixels.