What it looks like
Delphinus is a small but charming northern constellation, drawn as a dolphin leaping out of the water. Its brightest stars form a compact diamond shape, sometimes called Job's Coffin. Though tiny, it sits in a rich region beside the Summer Triangle, making it easy to find on summer and autumn evenings.
Brightest stars
Delphinus has no first-magnitude stars; its brightest four form a compact diamond near magnitude 4.
| Star | Magnitude | Distance | Meaning |
|---|---|---|---|
| Rotanev (β Delphini) | +3.63 | 97 ly | — |
| Sualocin (α Delphini) | +3.77 | 254 ly | — |
| Gamma Delphini | +4.27 | 101 ly | — |
| Delta Delphini | +4.43 | 223 ly | — |
Mythology and history
In Greek myth, Delphinus is the dolphin that rescued the poet Arion from pirates, or the one that carried Poseidon to his courtship of Amphitrite.
Two stories of the dolphin
One tradition tells of Arion, a poet and musician from Lesbos who was thrown overboard by pirates for his gold. A dolphin, charmed by his song, carried him safely to shore, and the dolphin was placed in the sky as reward. Another tradition identifies Delphinus with the dolphin sent by Poseidon to find the sea-nymph Amphitrite after she fled his advances. The dolphin found her, persuaded her to accept the god, and was placed among the stars for its service.
How to find it
Look for a compact diamond of faint stars just east of Altair in Aquila, inside the Summer Triangle.
- Find Altair, then look east for the small diamond.
- Delphinus is tiny but distinct — a good naked-eye test on a clear night.
- Best on summer and autumn evenings from both hemispheres.
Key facts
- Abbreviation
- Del
- Genitive
- Delphini
- Meaning
- The Dolphin
- Brightest star
- Rotanev
- Main stars
- 5
- Area rank
- 69th
- Best visible
- September
- Declination
- +10°
- Meteor showers
- —
- Neighbours
- Vulpecula, Sagitta, Aquila, Aquarius, Equuleus, Pegasus
Deep-sky objects
Delphinus contains several globular clusters, including NGC 6934 and NGC 7006, both of which are distant and faint. The constellation also contains the planetary nebula NGC 6891 and a handful of faint galaxies.
Frequently asked questions
What does the constellation Delphinus look like?
Delphinus is a small northern constellation known as the Dolphin, marked by a compact diamond of four stars that makes it one of the most recognisable small patterns in the sky.
What is the brightest star in Delphinus?
The brightest star in Delphinus is Rotanev, shining at around magnitude 3.63.
When is Delphinus best visible?
Delphinus is best seen from both hemispheres during September.
What is the story behind Delphinus?
In Greek myth, Delphinus is the dolphin that rescued the poet Arion from pirates, or the one that carried Poseidon to his courtship of Amphitrite.
Which constellations are near Delphinus?
Delphinus borders Vulpecula, Sagitta, Aquila, Aquarius, Equuleus and Pegasus.
Aquila
Sagitta