M40 (Winnecke 4)

M40 is a faint double star cataloged by Messier while searching for a nebula reported in error by Hevelius. This indicates some of the shortcomings of Messier's work which, while ground breaking and of inestimable value, was somewhat less than systematic. The pair was re-observed in 1863 and entered in the catalog compiled by A. Winnecke of the Pulkovo Observatory. M40 is several hundred light-years away and the two stars are probably close to, or only a few times, solar luminosity. KPNO 0.9-meter CCD image at f13.5, February 1996.