--- Patrick Wiggins <paw@trilobyte.net> wrote:
As your post came on the heels of Kurt's post about the nova in Sagittarius I'm not sure if you're talking about that or the supernova in M-51.
We're still talking M-51 and sn2005cs. For Joe - Using a common sense approach, and comparing your photo - http://www.utahastronomy.com/Joeb/m51color with http://www.astrosurf.com/snweb2/2005/05cs/05csHome.htm there is a common reference star in both photos with a V-band magnitude of 13.7. Looking at your photo, it seems there are stars going down to 14.5 (or dimmer), so its looks like sn2005cs would be within the reach of your scope and CCD setup. Spend a some time with your planetarium program and identify the dimmer stars in your photograph. That will give you a good feel for the photographic limiting magnitude of your specific telescope and camera combination. Joe, one of the variables, as Patrick pointed out, is the increased atmospheric extinction because M51 is now lower on the horizon. Your initial photo was taken in June. Other variables include that the sn is now fainter and its is inside a spiral arm of M51 that has its own surface brightness.
From the light curve of the sn, it is brighter in the IR and R (red) bands then in the V (visual) and B (blue) bands. So, if you use an IR blocking filter with your CCD, you might want to try taking it off for an exposure or two.
Let us know what you capture. - Enjoy Canopus56(Kurt) __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com