Yellow-white giant · Octans
α Octantis
Also known as: α Oct, HIP 104043
mag 5.1140 light-years
About
α Octantis is a yellow-white giant of magnitude 5.1 in Octans, about 140 light-years away.
How to find it
- α Octantis is in the constellation Octans.
- Best evenings: around late 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 south of 3° N.
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
| Designation | α Octantis (α Oct) |
|---|---|
| Hipparcos number | HIP 104043 |
| Type | Yellow-white giant |
| Spectral type | F4III |
| Colour | YellowB−V colour index 0.49 |
| Magnitude | 5.1The smaller the number, the brighter. |
| Distance | 140 light-yearsThe light you see left it around 1880. |
| Proper motion | 0.37″ per year across the sky |
| Constellation | Octans |
| Right ascension (J2000) | 21h 04m 43.0s |
| Declination (J2000) | −77° 01′ 26″ |
Sources and credits
Star data: HYG Database by David Nash, CC BY-SA 4.0. All data sources →