Star Stars · In Andromeda
Almach
Almach, γ¹ Andromedae, is a blue-white main-sequence star in Andromeda: the 63rd brightest star in the night sky.
Save the chart (SVG) Tactile chart (A4 SVG)
- Constellation
- Andromeda
- Designation
- γ¹ Andromedae
- Apparent magnitude
- 2.10 · 63rd brightest star in the night sky
- Spectral class
- B8V
- Distance
- 393 light-years
- Highest at midnight
- mid October
- Position (J2000)
- RA 02h 04m · Dec +42° 20′
A blue-white main-sequence star, around 14,000 K, like Rigel and Spica. About 58× brighter than the faintest star the eye can see. Gives off about 1,800 times the Sun's visible light. The light you are seeing left around 1633.
When to see it
On the night of Wed 20 Oct 2027, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT+1 | Never sets | 01:09 · 81° | — |
| New York EDT | 15:37 | 01:03 · 88° | 10:30 |
| Singapore GMT+8 | 19:10 | 01:14 · 49° | 07:18 |
| Sydney GMT+11 | 21:37 | 01:05 · 14° | 04:33 |
Common questions
- Can I see it from 50° north?
- Yes, on any clear night of the year — it is circumpolar from there and never quite sets, though at its lowest it skims the horizon, where trees and haze will hide it.
- Can I see it from 35° south?
- Yes. It rises and sets, and at its highest it stands 13° up in the north.
- When is the best time of year to see it?
- Around mid October, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by mid January it is highest in the early evening, and in mid July not until the hours before dawn.
- How far away is it, and how bright?
- It is 393 light-years away, and shines at magnitude 2.10 in our sky. From that far, the Sun would be a star of magnitude 10.2: too faint for the eye, a target for binoculars.
- Naked eye, binoculars or telescope?
- The naked eye, even from a city: at magnitude 2.10 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Algol: Almach is 12° west of it, a fist at arm’s length.
Look for
From 50° north it is circumpolar and never sets; from 35° north it climbs to 83°; from the equator it climbs to 48°; from 35° south it climbs to 13°.
Science
Almach’s surface is about 14,000 K, some 8,200 K hotter than the Sun’s 5,772 K, so its light is strongest at about 210 nm, in the ultraviolet, past the violet end of what the eye can see, 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 −3.3, brighter than Sirius, the brightest star in our sky.
Did you know
Against Algol, the brighter star the hop starts from: the two look about as bright as each other in our sky; Algol is 90 light-years away and Almach 393 light-years, so side by side Almach would give off 19 times as much light as Algol.
Science
Almach is the 114th nearest to us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is Mirfak, about 170 light-years from it; on our sky the two are 16° apart.
Look for
The Sun passes 28° south of Almach around mid April, when it is highest at noon, in daylight: the weeks either side are its worst time of year. From 35° north it is above the horizon for about 17 hours a day and from 35° south about 7. It is 19° from the plane of the Milky Way.