Delphinus the Dolphin can best be spotted at about 10 p.m. in the southeastern sky.

Jimmy Westlake/courtesy

Delphinus the Dolphin can best be spotted at about 10 p.m. in the southeastern sky.

Jimmy Westlake: Delphinus is high to southeast


Jimmy Westlake

Jimmy Westlake's Celestial News column appears Tuesdays in the Steamboat Today.

Find more columns by Westlake here.

— The late summer sky is dominated by several giant constellations that eat up a lot of territory: Hercules the Strong Man, Ophiuchus the Serpent Bearer, Ursa Major the Great Bear, etc. Tucked in between these sky-hogs are a few tiny constellations that are a snap to locate precisely because they are so small.

Delphinus the Dolphin is a case in point. Although Delphinus contains no star brighter than third magnitude, one's eye is immediately drawn to its small, distinctive diamond shape. To find Delphinus, go outside at about 10 p.m. and look high up in the southeastern sky, nearly overhead. There, you should spot summer's three brightest stars marking the corners of the Summer Triangle asterism: Vega, nearly straight up, Deneb, fainter and to the northeast, and Altair, to the southeast of Vega. Just east of Altair, you will spot the small diamond-shaped pattern of Delphinus the Dolphin. The four main stars form the head and body of the dolphin and a fifth star, off to the lower right, marks his tail. It requires little imagination to see a dolphin here, jumping up out of the celestial sea. You can just about cover the entire constellation of Delphinus with your thumb held at arm's length. The diamond-shaped asterism of Delphinus also is popularly known as "Job's Coffin," suspended halfway between heaven and Earth. The origin of this nickname is uncertain.

The Dolphin's two brightest stars are the ones marking the top and right points on the diamond. The origin of their unusual names, Sualocin and Rotanev, was a mystery for many years. They first appeared in a star catalog published by the Palermo Astronomical Observatory in Italy in 1814, but it was several decades later that British astronomer William Webb actually solved the riddle.

It seems that an observatory assistant named Nicolaus Venator was in charge of the star catalog project and that he played a practical joke on the rest of us. If you reverse the letters of the two star names, Sualocin and Rotanev, they spell Nicolaus Venator. Thus, the sneaky observatory assistant achieved immortality by naming two stars in Delphinus after himself.

The star at the tip of the dolphin's nose, named Gamma Delphini, is resolved with any small telescope into one of the most beautiful double stars in the heavens. Gamma's two colorful stars are just more than 100 light years from Earth and require 32 centuries to orbit each other. If you own a telescope, aim it at Gamma Delphini, the Dolphin's nose, for a real celestial treat.

Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College's Alpine Campus. He is an avid astronomer whose photographs and articles have been published all around the world. His "Celestial News" column appears weekly in the Steamboat Pilot & Today, and his "Cosmic Moment" radio spots can be heard on local radio station KFMU. Also, check out Jimmy's astrophotography Web site at


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