Star profile
Alpha Octans
Variable starWhat is Alpha Octans
Alpha Octantis is an eclipsing binary system: two near-identical F stars orbiting each other every nine days or so, mutually covering each other's light every 2.88 days in a dance of eclipses visible from Earth. She lives in Octans, the constellation framing the southern celestial pole, in a corner of sky where no bright southern pole star exists. At 142 light-years, she is a pair turning in silence on an invisible axis.
Where it is and when to see it
Alpha Octans lies in the southern celestial hemisphere. It is visible to the naked eye under a dark sky. Its best month of the year is July, when it culminates around midnight.
- From London it never rises above the horizon.
- From New York it never rises above the horizon.
- From Sydney it never sets and culminates about 47° up.
It can be seen from anywhere south of 13° N.
It ranks no. 7 in brightness among the 35 stars of Octans in our catalogue. To find it, start from Nu Octans, the brightest: it lies about 2° away (a fist at arm's length covers about 10°).
The light you see today left it about 140 years ago.
It opens in your browser. Free, no account, nothing to install.
Leave your signature on Alpha Octans
Your name and a message go up on the map for everyone to read. Signing is free.
Without a lock, someone else can replace your signature. How the lock works
We'll ask for an email to confirm it's you, no password.
A public signature from a real person. The chosen name is a symbolic denomination within Stelvia, with no official standing or IAU recognition: the sky is not for sale and belongs to no one.
Astronomical data for Alpha Octans
- Constellation
- Octans
- Apparent magnitude
- 5.13
- Distance
- 142.0 light years
- Coordinates (J2000)
- RA 316.179° · Dec -77.024°
- Catalogue
- HIP 104043 · HD 199532
A symbolic commemorative gift: neither the signature nor the chosen name implies ownership of the star or recognition by the IAU.
Other stars in Octans
Octans has 35 stars in Stelvia's catalogue. Here are a few of them.
- Nu Octans3.73
- Beta Octans4.13
- Delta Octans4.31
- Theta Octans4.78
- Epsilon Octans5.09
- Gamma 1 Octans5.10
- Lambda Octans5.27
- Gamma 3 Octans5.29