White main-sequence star
Alruba
Also known as: HIP 86782
mag 5.8530 light-years
About
Alruba is a white main-sequence star of magnitude 5.8, about 530 light-years away.
How to find it
- Best evenings: around early August 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 26° S.
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
- EyesNeeds a dark sky away from city lights.
- 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 | Alruba |
|---|---|
| Hipparcos number | HIP 86782 |
| Type | White main-sequence star |
| Spectral type | A2V |
| Colour | WhiteB−V colour index 0.02 |
| Magnitude | 5.8The smaller the number, the brighter. |
| Distance | 530 light-yearsThe light you see left it around 1490. |
| Proper motion | 0.021″ per year across the sky |
| Right ascension (J2000) | 17h 43m 59.2s |
| Declination (J2000) | +53° 48′ 06″ |
Sources and credits
Star data: HYG Database by David Nash, CC BY-SA 4.0. All data sources →