Star Stars · In Aquarius
Sadalmelik
Sadalmelik, α Aquarii, is a yellow supergiant in Aquarius: the 168th brightest star in the night sky.
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- Constellation
- Aquarius
- Designation
- α Aquarii
- Apparent magnitude
- 2.95 · 168th brightest star in the night sky
- Spectral class
- G2Ib
- Distance
- 524 light-years
- Highest at midnight
- mid August
- Position (J2000)
- RA 22h 06m · Dec −00° 19′
A yellow supergiant, around 5,800 K, like the Sun. About 26× brighter than the faintest star the eye can see. Gives off about 1,400 times the Sun's visible light. The light you are seeing left around 1502.
When to see it
On the night of Fri 20 Aug 2027, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT+1 | 19:13 | 01:11 · 38° | 07:09 |
| New York EDT | 19:07 | 01:06 · 49° | 07:04 |
| Singapore GMT+8 | 19:17 | 01:16 · 88° | 07:15 |
| Sydney GMT+10 | 18:08 | 00:07 · 56° | 06:07 |
Common questions
- Can I see it from 50° north?
- Yes. It rises and sets, and at its highest it stands 40° up in the south.
- Can I see it from 35° south?
- Yes. It rises and sets, and at its highest it stands 55° up in the north.
- When is the best time of year to see it?
- Around mid August, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by mid November it is highest in the early evening, and in late May not until the hours before dawn.
- How far away is it, and how bright?
- It is 524 light-years away, and shines at magnitude 2.95 in our sky. From that far, the Sun would be a star of magnitude 10.8: too faint for the eye, a target for binoculars.
- Naked eye, binoculars or telescope?
- The naked eye, even from a city: at magnitude 2.95 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Sadalsuud: Sadalmelik is 10° north-east of it, a fist at arm’s length.
Look for
From 50° north it climbs to 40°; from 35° north it climbs to 55°; from the equator it climbs to 90°; from 35° south it climbs to 55°.
Science
Sadalmelik’s surface is about 5,800 K, close to the Sun’s 5,772 K, so its light is strongest at about 500 nm, where the Sun’s is strongest at 500 nm. Moved to 33 light-years, the distance astronomers compare stars at, it would shine at magnitude −3.1, brighter than Sirius, the brightest star in our sky.
Did you know
Against Sadalsuud, the brighter star the hop starts from: the two look about as bright as each other in our sky; Sadalsuud is 537 light-years away and Sadalmelik 524 light-years, so side by side they would give off about as much light.
Science
Sadalmelik is the 131st nearest to us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is Sadalsuud, about 94 light-years from it; on our sky the two are 10° apart.
Look for
The Sun passes 11° south of Sadalmelik around mid February, when it is highest at noon, in daylight: the weeks either side are its worst time of year. From 50° north it is above the horizon for about 12 hours a day, from 35° north about 12 and from 35° south about 12. It is 42° from the plane of the Milky Way.