Delphinus
A tiny dolphin leaping in summer
Best on June–August evenings · northern sky.
Delphinus is a small but surprisingly easy constellation, tucked in a rich patch of the summer Milky Way. It's best known for its tight four-star diamond — sometimes called Job's Coffin — which looks remarkably like a leaping dolphin when you add the tail star below it.
How to find it
On summer evenings from the northern hemisphere, find brilliant Altair in Aquila — one of the three stars of the Summer Triangle. Delphinus lies just a short hop to the northeast of Altair; once you're in that area, the compact four-star diamond pops out almost immediately against the fainter background.
Brightest stars
Beta Delphini, named Rotanev, leads at magnitude 3.63, with alpha star Sualocin just behind at 3.77 — the two are close enough that they appear as a matched pair at the near corner of the diamond.
Worth seeing
The four-star diamond itself is the reward — it's remarkably compact and geometric, and spotting this little pattern amid the summer Milky Way gives a real sense of how much the sky rewards careful looking.
Frequently asked
When is Delphinus visible?
Summer evenings, roughly June through August, when it rides well up in the northern sky from northern latitudes.
What are the brightest stars in Delphinus?
Rotanev (β Del, magnitude 3.63) and Sualocin (α Del, magnitude 3.77) are the brightest, forming part of the compact four-star diamond asterism.
Is Delphinus visible from the southern hemisphere?
Yes, though it sits in the northern sky and is better placed from northern latitudes. Southern observers can still catch it low in the north on summer nights.
Nearby constellations
Aquila · Cygnus · Pegasus · Capricornus · Lyra · Aquarius · Sagittarius · Hercules