AndromedaAriesPerseusPisces- Star Tales - Triangulum (ianridpath.com)
Since any three points make up the corners of a triangle it is unsurprising, if somewhat unimaginative, to find a triangle among the constellations. Aratus and Eratosthenes knew this constellation as Δελτωτόν (Deltoton), because its shape resembled a capital delta (Δ), while Ptolemy in the Almagest listed it as Τρίγωνον (Trigonon), triangle.
- Triangulum (Wikipedia)
Triangulum is a small constellation in the northern sky. Its name is Latin for “triangle”, derived from its three brightest stars, which form a long and narrow triangle. Known to the ancient Babylonians and Greeks, Triangulum was one of the 48 constellations listed by the 2nd century astronomer Ptolemy. The celestial cartographers Johann Bayer and John Flamsteed catalogued the constellation’s stars, giving six of them Bayer designations.