Delphinus constellation
Delphinus (the Dolphin) is a constellation in the northern sky, best seen in the evening in September. Its brightest star is Rotanev (magnitude 3.63). Delphinus covers 189 square degrees and is the 69th-largest of the 88 constellations.
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Detailed star map of Delphinus
Facts
| Latin name | Delphinus (genitive: Delphini) |
|---|---|
| Abbreviation | Del |
| Meaning | the Dolphin |
| Area | 189 square degrees (69th of 88) |
| Location | right ascension 20.7 h, declination +12° |
| Visible from | latitudes 90° N to 69° S (whole constellation) |
| Best month | September (at about 9 pm) |
| Brightest star | Rotanev |
| Stars brighter than magnitude 6 | 20 |
| Named stars (IAU) | 4 |
| Messier objects | none |
| Neighbors | Aquila, Aquarius, Equuleus, Pegasus, Sagitta, Vulpecula |
How to find Delphinus
From 40° N (the USA, southern Europe, Japan) look south in September evenings: at about 9 pm Delphinus stands highest, around 62° above the southern horizon. From 35° S (Australia, South Africa, Argentina) it is highest in the north, about 43° above the horizon. The months before and after (August and October) are also good: then it is up a couple of hours earlier or later.
Delphinus borders Aquila, Aquarius, Equuleus, Pegasus, Sagitta and Vulpecula.
Stars of Delphinus
Delphinus has 20 stars brighter than magnitude 6, the limit of the naked eye under a dark sky. These are the brightest:
| Star | Designation | Magnitude | Type | Distance |
|---|---|---|---|---|
| Rotanev | β Delphini | 3.63 | F5IV | — |
| Sualocin | α Delphini | 3.77 | B9IV | 238 ly |
| Aldulfin | ε Delphini | 4.03 | B6III | 366 ly |
| — | γ2 Delphini | 4.27 | K1IV | — |
| — | δ Delphini | 4.43 | A7IIIpDel Del | — |
Printable Delphinus map and outline
A black and white version for printing and a plain outline of the Delphinus figure, useful for school projects, worksheets and learning to recognize the shape.
History
Delphinus is one of the 48 constellations listed by Ptolemy in the Almagest (2nd century AD). Its official boundary was drawn by Eugène Delporte for the International Astronomical Union in 1930.
Questions about Delphinus
What is the brightest star in Delphinus?
Rotanev, at magnitude 3.63.
When can you see Delphinus?
Delphinus is best seen in the evening in September. The whole constellation is visible from latitudes between 90° N and 69° S.
How many stars are in Delphinus?
20 stars in Delphinus are brighter than magnitude 6 and can be seen with the naked eye under a dark sky; 4 of them have official IAU names.
What does Delphinus mean?
Delphinus means “the Dolphin” in Latin. Its abbreviation is Del and the genitive, used in star names such as β Delphini, is Delphini.
