Combination of 15, 1 minute images unfiltered.
SBIG STL-1001E CCD. 20" f/6.8 Dall-Kirkham cassegrain telescope at prime focus.
NGC 2539 is a large, scattered cluster of moderately bright stars in Puppis. On the south-east edge of the cluster is the 4th magnitude star SAO 153942. This bright K-type giant star is not a member of the cluster. At a distance of about 185 lightyears, it is only a foreground object.