Double Star M40 (WNC 4) in Ursa Major Winnecke 4

RA 12 : 22.4 (h:m); DEC +58 : 05 (deg:m); Distance 0.51 (kly); Visual Brightness 8.4 (mag); Apparent Dimension 0.8 (arc min)
This faint double star was found by Charles Messier when he was searching for a nebula which was - erroneously - reported by the 17th-century observer Johann Hevelius in this vicinity.
According to his catalog description, Messier did not see any nebulosity associated with them.
As Messier had measured the position of these stars, he gave them a number in his catalog.

Source and more: SEDS

March 20, 2006 23:10 - 23:16 UT.
Imaged with LX200 10-inch f/10 telescope with 0.33 Focal Reducer operating at f/4.06 [focal length 1015mm], Vesta Pro-SC3a b/w RAW mode, Baader Infra Red Blocking Filter.
20 autoguided exposures of 10 seconds.