Sagitta the Arrow is a constellation found within the Summer Triangle and containing one of Messier's globular clusters.
Sagitta the Arrow has been associated with a variety of different mythological persons, including Hercules and Apollo. It is also understandable to relate the well-known constellation of Sagittarius the Archer with Sagitta the Arrow. However, the two do not lie next to each other in the sky. Sagittarius can be found low on the southern horizon in summer while Sagitta is farther north. It almost appears as if Sagittarius has shot his arrow at Aquila the Eagle and missed, and the arrow (Sagitta) can be found on the other side of Aquila from Sagittarius.
Locating the Constellation of Sagitta
Although Sagitta is small and dim, its general region can be easily found because of its position inside the Summer Triangle. Sagitta and Vulpecula are the two constellations that take up residence between the constellations Cygnus, Lyra, and Aquila. Each of those constellations has one bright star that marks the corners of the triangle: Cygnus's star is Deneb, Lyra's star is Vega, and Aquila's star is Altair.
Sagitta lies 10 degrees north of Altair. Vulpecula lies north of Sagitta. The small but favorite constellation of Delphinus lies just to Sagitta's east.
Stars of Sagitta the Arrow
The constellation Sagitta the Arrow is usually considered the third smallest of the 88 constellations. Equuleus the Little Horse in the Northern Hemisphere and Crux the Southern Cross in the Southern Hemisphere are both smaller. Equuleus lies a short distance from Sagitta (on the other side of Delphinus).
Because of its small size there are few observing targets in Sagitta. The brightest star is Gamma Sagittae, a magnitude 3.51 point that lies 274 light-years away. About three degrees west is Delta Sagittae, a magnitude 3.68 star lying 448 light-years away. Then just a bit less than two degrees west of Delta are two stars both at magnitude 4.38. The one slightly north is Alpha Sagittae and the one slightly south is Beta Sagittae. Alpha lies 473 light-years from Earth, while Beta lies 467 light-years away from us.
Sagitta's Messier Object
The one notable deep-sky target in Sagitta is also its only Messier object: M71. M71 can be found halfway between the stars Gamma and Delta. At magnitude 8.3, this globular cluster is best seen through binoculars or a telescope. Because of M71's appearance, it was long believed to be an open cluster with a rather dense center. It is now taken to be a looser, smaller globular cluster. Measurements have placed M71 at about 13,000 light-years distant.
