Yellow-white subgiant · Delphinus
Rotanev
Also known as: β Delphini (β Del), HIP 101769
mag 3.6100 light-years
About
Rotanev (β Delphini) is a yellow-white subgiant of magnitude 3.6 in Delphinus, about 100 light-years away.
How to find it
- Rotanev is in the constellation Delphinus.
- Best evenings: around mid-September it is highest at about 9 pm (10 pm in summer time); a month earlier, two hours later.
- Where on Earth: it is seen well, at least 10° up, from north of 65° S.
- Star patterns: Job’s Coffin.
When it rises and sets tonight, how high it climbs and how much the Moon gets in the way are worked out in your browser for your place.
What you will see
- EyesVisible from the suburbs on a clear night, but lost in bright city skies.
- Binoculars (10×50)A sharp point; binoculars bring out its colour and the fainter stars around it.
- Telescope (6–8 inch)Still a point of light at any magnification — stars are too far away to show a disc. Low in the sky, bright stars twinkle and flash colours.
Stars look the same in any instrument: brighter and sharper, but never bigger.
Facts
| Proper name | Rotanev |
|---|---|
| Designation | β Delphini (β Del) |
| Hipparcos number | HIP 101769 |
| Type | Yellow-white subgiant |
| Spectral type | F5IV |
| Colour | Yellowish whiteB−V colour index 0.42 |
| Magnitude | 3.6The smaller the number, the brighter. |
| Distance | 100 light-yearsThe light you see left it around 1930. |
| Proper motion | 0.13″ per year across the sky |
| Constellation | Delphinus |
| Right ascension (J2000) | 20h 37m 32.9s |
| Declination (J2000) | +14° 35′ 42″ |
More in Delphinus
NGC 6934Globular clustermag 8.8
NGC 7006Globular clustermag 10.6_-_RHaBOIII.png?width=160)
NGC 6905Blue Flash NebulaPlanetary nebula · mag 11.1Sources and credits
Star data: HYG Database by David Nash, CC BY-SA 4.0. All data sources →