Another M51 from the backyard

by Richard Crisp

Also since the seeing was less than optimal, i changed my image scale to be less oversampled in hopes of having a brighter image in less time and with sharper stars.

Here's the result from last night, processed pretty quickly. it is a total of 1.5 hours exposure. The binning I used makes this exposure equivalent in depth and signal to noise ratio closer to a 4x longer exposure that is unbinned. So my five minute subexposures were equivalent to 20 minute unbinned exposures.

New binned image

http://www.narrowbandimaging.com/m51_mk1sn2_cm10_lum_2x2_page.htm

Old unbinned image from the night before

http://www.narrowbandimaging.com/m51_mk1sn2_cm10_geg_page.htm

Also with the help of a friend, Carl Burton, I was able to determine that, when using the Lumicon reducer, my focal length is 3345mm which is equivalent to f/7.31. This compares to F=5760mm and f/12.6 without the reducer.

Posted on sf-bay-tac Apr 20, 2006 07:00:46 PT
Converted by report.pm 1.4 Apr 23, 2006 08:11:43 PT