Altair
star · Aquila · 0.8ᵐ
It spins so fast — under nine hours per rotation — that it is visibly flattened, its equatorial diameter a quarter larger than the polar one.
Notable facts
About 125 times brighter than the faintest star visible to the naked eye.
In brief
Which constellation is Altair in?
Altair lies in Aquila.
Is Altair visible to the naked eye?
0.8ᵐ — visible to the naked eye (under dark skies).
When is the best time to observe Altair?
Best observed in July.
Data
- RA / Dec (J2000)
- 19h 51m · +8° 52′
- Type
- star
- Constellation
- Aquila
- How to observe
- 0.8ᵐ — visible to the naked eye (under dark skies)
- Spectral class
- A7IV-V — white star
- Absolute magnitude
- 2.2ᵐ
- Luminosity
- ≈11 × the Sun
- Distance
- ~17 light years
- Designation
- HIP 97649
Observing tip
Stars stay points at any magnification: aim your telescope for colour, brightness and companions, not detail.
Altitude above the horizon by latitude
| Latitude | Maximum altitude | Rise azimuth |
|---|---|---|
| +60° | 39° | 72° |
| +55° | 44° | 74° |
| +45° | 54° | 77° |
| +30° | 69° | 80° |
| 0° | 81° | 81° |
| −35° | 46° | 79° |
Geometric altitude at upper culmination, atmospheric refraction not included. Positive latitudes are in the northern hemisphere.
Culmination time by month
| Month | Culmination |
|---|---|
| January | 12:05 |
| February | 09:58 |
| March | 08:13 |
| April | 06:19 |
| May | 04:25 |
| June | 02:19 |
| July | 00:15 |
| August | 22:14 |
| September | 20:21 |
| October | 18:32 |
| November | 16:31 |
| December | 14:23 |
Upper culmination in local solar time — no time-zone or daylight-saving correction applied.