DELPHINUS (pronounced del-FIE-nes), the Dolphin
EQUULEUS (pronounced eh-KWOO-lee-us), the Little Horse
Delphinus, the Dolphin originated in ancient Greek times and celebrates the long standing relationship between man and the most intelligent of sea creatures. Ptolemy assigned 10 stars to it. In legend dolphins were the messenger of the sea god Poseidon, and were credited with saving the life of Poseidon's son, Arion, when he was attacked on a ship. The constellation has a distinctive shape, with its four main stars forming a rectangle known as Job's Coffin. Its two brightest stars are called Sualocin and Rotanev, which backwards read Nicolaus Venator, the Latinized form of the Name Niccolo Cacciatore, who was assistant to the Italian astronomer Guiseppe Piazzi.
Equuleus, the Little Horse or Foal, seems to have originated by Hipparchus about 150 BC, for some small stars near Delphinus. Ptolemy, four centuries later only assigned four stars to it. One myth sees it as Celeris, the brother of neighboring Pegasus.
To find these constellations look north in the evening between the Great Square of Pegasus and the bright star Altair. Delphinus is the easiest to see with its distinctive shape.
Chart showing the constellations as seen to the north at about 9.30 pm (NZST) mid September.
The horizon is for southern New Zealand
Some stars and interesting objects in the Constellations
α Delphini (Sualocin) is a magnitude 3.8 blue-white star 241 light years away.
β Del (Rotanev), is magnitude 3.5 white star 97 light years away.
γ Del is a beautiful bright pair of stars, making an attractive sight for small aperture telescopes. It consists of golden and yellow-white stars of magnitudes 4.3 and 5.2, 101 light years away. In the same field of view is a fainter double star Struve 2725, consisting of stars of 7th and 8th magnitude.
α Equulei (Kitalpha, little horse) is a magnitude 3.9 yellow giant star 186 light years away.
γ Equ is a slightly variable white star of magnitude between 4.58 and 4.77, 115 light years away. There is also a close faint companion, which is not easy to see.
ε Equ appears to be a triple star 197 light years away in telescopes. The orbit of the close yellow pair is near to the line of sight with a period of 101 years. The stars are now closing and more difficult to separate. There is a wider third star, easily seen. The brightest star is actually a spectroscopic binary star with a period of 2.03 days, so in reality this is a quadruple star system. The star is also known as 1 Equ.
Delphinus and Equuleus are some 10° north of the equator so achieve a moderate altitude in New Zealand. They are visible from April, in the pre-dawn morning sky to the north-east through to October when they are visible to the north-west after evening twilight.
The constellations are due north and at their highest at about 9.30 to 10.00 pm NZST in mid September, an hour later at the beginning of the month and an hour earlier by October 1