Almost in the afternoon weather was already promising and when I returned home from work I set up the mount and the scope. After I put the children into bed I started getting the stuff ready. But the autoguider system with the AlphaMini CCD controlled by AstroArt 3.0 refused operating. It took me about an hour to persuade it to continue ... I had planned to image M81/M82 and M51, but as time became late I decided to concentrate on M51 only. Focusing and imaging with ImagesPlus 2.75 is easy and things went almost flawlessly for the next 90 minutes to take 10 images of 5 minutes each and the appropriate dark, bias and flat fields. For flatfields I first time used the notebook screen with a uniform gray background fullscreen. But still I have problems reducing the amplifier glow in the upper left corner.
The images below are from the same frame at different resolutions.
Last Update: 29 March 2006
M51 Whirlpool Galaxy Field
Also visible are below M51 (from left) NGC5198 (mag 12,7), NGC5173 (mag 13,2) and NGC5169 (mag 14,4). In the upper left corner NGC5229 (mag 14,4). Looking deeply to the image, there are some more galaxies on this image at aroud 16 mag.
NIKON D70 at ISO1600
Stellarvue NightHawk (AT1010 / Classic) 80/480mm Achromatic Refractor / BAADER "Fringe Killer" Filter
20 March 2006 2200 UT 8 * 300sec and 2 * 60sec
Image treated with ImagesPlus 2.75 and Paintshop Pro 5 (for higher JPG compression)
M51 Whirlpool Galaxy Center of Image
Magnitudes in this image are supposed to be somewhat better than 16 mag.
NIKON D70 at ISO1600
Stellarvue NightHawk (AT1010 / Classic) 80/480mm Achromatic Refractor / BAADER "Fringe Killer" Filter
20 March 2006 2200 UT 8 * 300sec and 2 * 60sec
Image treated with ImagesPlus 2.75 and Paintshop Pro 5
M51 Whirlpool Galaxy Whole Frame Size reduced
Still some red amplifier glow is visible. I could not filter it away.
Some comments from the Web
Hi Christoph! That's an excellent image! Is the close up of the galaxy taken from the bottom image? Søren
Very nice. We have some of the same objects in mind. I will give M51 another go tonight, as it finally has cleared up. IP 2.75 has a dark frame/amp glow option that removes the ampglow effectively. I see that you are using an "Old" version of Paint Shop Pro. I suggest moving to PSP 9 or 10, as they have many routines that are favorable to astro- processing. Ciao...Barry
Very good, especially for an achromat. Very little blue goo. Do you use a Fringe Killer or IDAS filter ? Either reduce the blue goo, but I think the FK is better at reducing ca, and the IDAS better at overall light pollution, with ca reduction a secondary function. I was anxious to try Baader's Semi-APO filter, but they seem to have some problem producing it in the 48mm size. It looks like the semi- apo filter will be close in performance to the IDAS for light pollution, but with more blue ca improvement in achros. I tried M51 several times, but conditions must have been bad for me, so I will get it in the future. PS: I found your website and it shows that you do use a Fringe Killer. eldoo
Christoph, The first image (Galaxy Field) is my favorite. Beautiful detail! Clear, dark skies, Jim S. Redlands, CA
Christoph, Great widefield image of M51! Nice detail and pinpoint stars. Thanks for sharing. Clear skies, Dave Weixelman Nevada City, CA
Nice image. Do you have fairly dark skies? cheers, Duncan
Super Christoph. Nicely done. The galaxy stands out well from the background. Jon Talbot