TRIANGULUM "The Triangle" (Pronounced tri-ANG-gyah-lum).

Chart showing the constellation.

Triangulum is small but distinctive constellation lying below Aries, with three main stars forming a delta shape. It is an ancient constellation to which Ptolemy assigned four stars. The Greeks referred to the constellation as Deltotron.

To find the constellation look north late evening, between the bright star Aldebaran in Taurus and the "Great Square of Pegasus".

Chart showing Triangulum - as seen about 10.00 to 10.30 pm (NZDT) mid December.

Triangulum chart

Constellation Cetus Constellation Auriga Constellation Perseus Constellation Aries Constellation Taurus Constellation Pisces Constellation Pegasus Constellation Andromeda

Some stars and interesting objects in the Constellation

α Trianguli is a magnitude 3.4 white star 64 light years away.

β Tri is a magnitude 3.0 white star 124 light years away.

γ Tri is a magnitude 4.0 blue white star 118 light years away.

6 Tri is a pair of bright golden yellow stars, dominating a field of faint stars. This pair is an easy object for small apertures. Each star is the system is actually a spectroscopic binary pair of stars with periods of 14.73 and 2.24 days lying 305 light years away.

M 33 (NGC 598) is a spiral galaxy known as the "Pinwheel or Triangulum Galaxy". It is a galaxy seen almost face-on, and was discovered by Messier in 1764. It lies about three million light years away and is the third largest member in size of the Local Group of Galaxies, following the Andromeda Galaxy and our own Milky Way Galaxy. M 33 is best picked up in binoculars or small telescopes using low powers to increase the contrast. Quite large telescopes are needed to trace out the spiral arms.


Triangulum is well north of the equator and does not rise high in New Zealand skies. α Tri reaches an altitude of about 24° in Auckland, but only 14° as seen from Invercargill. Look for the constellation low to the north as soons as the sky is dark following sunset in December and January. It will be to the north close to midnight in mid November.