The Stars of Orion’s Belt (evening)

Orion’s three belt stars are bright enough to tolerate tonight’s moonlight. They may look similar, but they are quite different, under closer inspection. The left-most (easterly) of the three, magnitude 1.85 Alnitak (Zeta Orionis) is bluer. In a telescope, Alnitak (Arabic for “the Girdle”) is revealed to be a very tight magnitude 1.85 double star. At 1,976 light-years from our sun, the middle star, Alnilam (Epsilon Orionis) is more than twice as far away as the other two. At the right-hand (western) end of the row, magnitude 2.4 Mintaka (Delta Orionis) is a more widely spaced double star. Using binoculars (orange circle) look for a large, upright, S-shaped asterism of dim stars in the space between Alnilam and Mintaka. The medium-bright star sitting less than a finger’s width below (or 0.8 degrees southwest of) Alnitak is Sigma Orionis, a beautiful little grouping of ten or more stars.