Description of Delphinus
Delphinus is a constellation in the northern sky, close to the celestial equator. Its name is Latin for dolphin. Delphinus was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains among the 88 modern constellations recognized by the International Astronomical Union. It is one of the smaller constellations, ranked 69th in size.
Delphinus' brightest stars form a distinctive asterism that can easily be recognized. It is bordered (clockwise from north) by Vulpecula the fox, Sagitta the arrow, Aquila the eagle, Aquarius the water-carrier, Equuleus the foal and Pegasus the flying horse.
Points of Interest
A double star. A small telescope will separate the two components, which appear yellow and white, of magnitudes 4.3 and 5.2. Both stars lie approximately 100 light-years away. A fainter and closer pair of 8th-magnitude stars, known as Struve 2725 (about 125 light-years away), should be visible in the same field of view.
A name given to the box shape formed by the four stars Alpha, Beta, Gamma and Delta Delphini, all of which are of 4th magnitude.