Rasalgethi
star · Hercules · 2.8ᵐ
Red star in Hercules.
Notable facts
The light you see today left Rasalgethi around the year 1666.
About 19 times brighter than the faintest star visible to the naked eye.
In brief
Which constellation is Rasalgethi in?
Rasalgethi lies in Hercules.
Is Rasalgethi visible to the naked eye?
2.8ᵐ — visible to the naked eye (under dark skies).
When is the best time to observe Rasalgethi?
Best observed in June.
Data
- RA / Dec (J2000)
- 17h 15m · +14° 23′
- Type
- star
- Constellation
- Hercules
- How to observe
- 2.8ᵐ — visible to the naked eye (under dark skies)
- Spectral class
- M5IIvar — red star
- Absolute magnitude
- -2.4ᵐ
- Luminosity
- ≈802 × the Sun
- Distance
- ~360 light years
- Designation
- HIP 84345
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° | 44° | 60° |
| +55° | 49° | 64° |
| +45° | 59° | 69° |
| +30° | 74° | 73° |
| 0° | 76° | 76° |
| −35° | 41° | 72° |
Geometric altitude at upper culmination, atmospheric refraction not included. Positive latitudes are in the northern hemisphere.
Culmination time by month
| Month | Culmination |
|---|---|
| January | 09:29 |
| February | 07:22 |
| March | 05:37 |
| April | 03:43 |
| May | 01:49 |
| June | 23:43 |
| July | 21:39 |
| August | 19:38 |
| September | 17:45 |
| October | 15:56 |
| November | 13:55 |
| December | 11:47 |
Upper culmination in local solar time — no time-zone or daylight-saving correction applied.