Delphinus
Delphinus, the little dolphin leaping beside the Milky Way. With its dainty rhombus shape, it carries the tale of the dolphin that saved a musician.
Science
The scienceDelphinus is small and faint, yet its stars huddle close to form a distinct dainty rhombus (the dolphin's body) with a short tail, making it surprisingly easy to find at the edge of the Milky Way. The names of its chief and second stars, "Sualocin" and "Rotanev," hold an amusing secret: Niccolò Cacciatore, an assistant at the Palermo Observatory in the 19th century, slyly gave them by reversing his own Latinized name, Nicolaus Venator.
Mythology
How it became a constellationWhen the nymph Amphitrite, whom the sea god Poseidon wished to marry, fled and hid herself, Poseidon sent a dolphin to find her and win her over. When the dolphin carried out its task splendidly, Poseidon honored the deed by setting it among the stars as a constellation. In another tale, the musician Arion, seized by sailors and thrown into the sea, was carried safely to shore on the back of a dolphin enchanted by his beautiful song.
Observing Guide
how to observe🔭 How to find it
Inside the Summer Triangle (Vega, Altair, and Deneb), move a little northeast from Altair (in Aquila) and you'll see a dainty diamond of small stars clustered close together — this is Delphinus. Its clear shape — a diamond (the dolphin's body) with a short tail attached — means that despite its small size, it's surprisingly easy to spot at the edge of the Milky Way. It's also nicknamed "Job's Coffin."
✨ What to look for
For such a small constellation, Delphinus holds two globular clusters: NGC 6934, and the more distant and fainter NGC 7006 — both requiring a medium or larger telescope. There's also a planetary nebula, NGC 6905, known as the "Blue Flash Nebula." On the whole, though, bright targets are few, so it's more rewarding simply to enjoy the constellation's charming little shape.
📍 Where to see it (US · Canada · UK · Australia)
At +11° to +16° declination, Delphinus is well placed for northern observers, riding high in the south on summer-to-early-autumn nights (July–October) from the US, Canada, and the UK; because its stars are faint, the little diamond stands out best under a dark sky. From Australia the dolphin appears in the northern sky during the southern winter and spring — lower down, but still easy to pick out.