Ophiuchus constellation
Ophiuchus (the Serpent Bearer) is a constellation on the celestial equator, best seen in the evening in July. Its brightest star is Rasalhague (magnitude 2.08). Ophiuchus covers 948 square degrees and is the 11th-largest of the 88 constellations.
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Detailed star map of Ophiuchus
Facts
| Latin name | Ophiuchus (genitive: Ophiuchi) |
|---|---|
| Abbreviation | Oph |
| Meaning | the Serpent Bearer |
| Area | 948 square degrees (11th of 88) |
| Location | right ascension 17.4 h, declination −6° |
| Visible from | latitudes 60° N to 76° S (whole constellation) |
| Best month | July (at about 9 pm) |
| Brightest star | Rasalhague |
| Stars brighter than magnitude 6 | 86 |
| Named stars (IAU) | 7 |
| Messier objects | M9, M10, M12, M14, M19, M62, M107 |
| Neighbors | Aquila, Hercules, Libra, Scorpius, Serpens, Sagittarius |
How to find Ophiuchus
From 40° N (the USA, southern Europe, Japan) look south in July evenings: at about 9 pm Ophiuchus stands highest, around 44° above the southern horizon. From 35° S (Australia, South Africa, Argentina) it is highest in the north, about 61° above the horizon. The months before and after (June and August) are also good: then it is up a couple of hours earlier or later.
Ophiuchus borders Aquila, Hercules, Libra, Scorpius, Serpens and Sagittarius.
Stars of Ophiuchus
Ophiuchus has 86 stars brighter than magnitude 6, the limit of the naked eye under a dark sky. These are the brightest:
| Star | Designation | Magnitude | Type | Distance |
|---|---|---|---|---|
| Rasalhague | α Ophiuchi | 2.08 | A5III | — |
| Sabik | η Ophiuchi | 2.43 | A2V | — |
| — | ζ Ophiuchi | 2.56 | O9.5Vn | — |
| Yed Prior | δ Ophiuchi | 2.74 | M0.5III | 160 ly |
| Cebalrai | β Ophiuchi | 2.77 | K2III | 83 ly |
| — | κ Ophiuchi | 3.2 | K2III | — |
| Yed Posterior | ε Ophiuchi | 3.24 | G9.5IIIbFe-0.5 | 108 ly |
| — | θ Ophiuchi | 3.27 | B2IV | — |
| — | ν Ophiuchi | 3.34 | K0IIIaCN-1 | — |
| — | 72 Ophiuchi | 3.73 | A4IV s | — |
| — | γ Ophiuchi | 3.75 | A0Vnp | — |
| Marfik | λ Ophiuchi | 3.82 | A0V+A4V | — |
Deep-sky objects in Ophiuchus
Ophiuchus contains 7 objects from Charles Messier's catalog:
- Messier 9 (M9): globular cluster, 8.4 mag
- Messier 10 (M10): globular cluster, 5.0 mag
- Messier 12 (M12): globular cluster, 6.1 mag
- Messier 14 (M14): globular cluster, 5.7 mag
- Messier 19 (M19): globular cluster, 5.6 mag
- Messier 62 (M62): globular cluster, 7.4 mag
- Messier 107 (M107): globular cluster, 8.9 mag
Printable Ophiuchus map and outline
A black and white version for printing and a plain outline of the Ophiuchus figure, useful for school projects, worksheets and learning to recognize the shape.
History
Ophiuchus 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 Ophiuchus
What is the brightest star in Ophiuchus?
Rasalhague, at magnitude 2.08.
When can you see Ophiuchus?
Ophiuchus is best seen in the evening in July. The whole constellation is visible from latitudes between 60° N and 76° S.
How many stars are in Ophiuchus?
86 stars in Ophiuchus are brighter than magnitude 6 and can be seen with the naked eye under a dark sky; 7 of them have official IAU names.
What does Ophiuchus mean?
Ophiuchus means “the Serpent Bearer” in Latin. Its abbreviation is Oph and the genitive, used in star names such as α Ophiuchi, is Ophiuchi.
