While searching for the nebula above the back of Ursa Major, reported in the book Figures des Astres, and which is supposed to be for 1660 at 183d 32» 41»
right ascension, & 60d 20» 33» northern declination, which Messier couldn't
see, he has observed these two stars.»
If I remember
right, the author stated that when the beetle did eventually make the
ascension over the Rockies, their numbers were so vast that you could
see the «cloud» from satellites.