The Owl Nebula, located in Ursa Major the Great Bear, is one of only four planetary nebulae on Messier’s list. Looking for a sky event this week? Check out our full Sky This Week column. March 12: Europa and its shadow cross Jupiter Look north this evening for Ursa Major the Great Bear, whose back half is best known as the Big Dipper. The two stars on the far... [1078 chars]