Brian Jones: Delphinus
Delphinus is a small but very distinctive diamond-shaped pattern of stars which can be found a little way to the east of the bright star Altair in Aquila. Once Altair is located (see last month’s blog) and provided the sky is fairly dark and clear, Delphinus can be found by using the accompanying star chart. If you have problems locating this tiny constellation, binoculars will bring it out very well.
According to a Greek legend, there was once a talented poet and musician called Arion. He made his fortune in Italy and eventually decided to return to Greece. However, the sailors on board the ship taking him home plotted to kill him and steal his wealth. They did allow Arion a last wish, letting him play some of his favourite music before he died. However, before he had finished, the sailors noticed that a school of dolphins had been attracted to the ship by Arion’s harp. Terrified by the apparent power of his music, they threw him overboard. Luckily, Arion landed on the back of one of the dolphins and was eventually carried to the safety of land. As a reward, Neptune placed the dolphin up among the stars where he can be seen to this day.
A somewhat macabre alternative name for the group is Job’s Coffin, although the origin of this name is obscure. It has also been associated with the whale that swallowed Jonah. To the ancient Chinese the group was known as a gourd. A degree of controversy surrounds the origin of the names given to the two brightest stars in Delphinus. When spelled backwards, Sualocin and Rotanev read as Nicolaus Venator, which is the Latinized version of Niccolo Cacciatore. This gentleman was the assistant to Guiseppe Piazzi, the director of the Palermo Observatory in Sicily during the early 19th century. Cacciatore succeeded Piazzi as director and these two names first appeared in the observatory’s 1814 star catalogue. To say that this is a rather unusual origin for star names is something of an understatement.
Sualocin is blue-white in colour while Rotanev has a yellowish tint. Binoculars, and really clear skies, will show this colour difference. The two stars are almost identical in brightness. Gamma Delphini is a pretty double star which can be resolved in a small telescope. Both components have a yellowish hue. Gamma lies at a distance of around 100 light years, which means we are seeing it as it was around the time King Edward VII came to the throne.
Delta Delphini is a white star and Epsilon has a slightly bluish tint. Epsilon is sometimes referred to as Deneb, meaning the Tail of the Dolphin. Deneb is a common star name and crops up in many other constellations in one form or another, including Deneb in Cygnus (the Swan), Denebola in Leo (the Lion) and Deneb Algiedi in Capricornus (the Goat).
As we have seen, the constellation Delphinus was known to the Ancient Chinese astronomers as the gourd and, in keeping with this, the rather unusual name they gave to Epsilon was Pae Chaou, the Rotten Melon! Whatever spin you put on the name of this tiny but pretty pattern of stars, it is well worth seeking out in the late-summer night sky! Happy stargazing!