Star Stars · In Cassiopeia
Cih
Cih, γ Cassiopeiae, is a blue-white subgiant in Cassiopeia: the 65th brightest star in the night sky.
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- Constellation
- Cassiopeia
- Designation
- γ Cassiopeiae
- Apparent magnitude
- 2.15 · 65th brightest star in the night sky
- Spectral class
- B0IV:evar
- Distance
- 549 light-years
- Highest at midnight
- early October
- Position (J2000)
- RA 00h 57m · Dec +60° 43′
A blue-white subgiant, around 30,000 K, like Rigel and Spica. About 55× brighter than the faintest star the eye can see. Gives off about 3,300 times the Sun's visible light. The light you are seeing left around 1477.
When to see it
On the night of Sun 3 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 | Never sets | 01:03 · 70° | — |
| Singapore GMT+8 | 19:05 | 01:14 · 30° | 07:23 |
| Sydney GMT+11 | Never rises | ||
Common questions
- Can I see it from 50° north?
- Yes, on any clear night of the year. From there it never sets: it is circumpolar, circling the pole and still 21° up at its lowest.
- Can I see it from 35° south?
- No. From there it never rises: you would have to travel north of 29° south before it cleared the horizon at all.
- When is the best time of year to see it?
- Around early October, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by early January it is highest in the early evening, and in early July not until the hours before dawn.
- How far away is it, and how bright?
- It is 549 light-years away, and shines at magnitude 2.15 in our sky. From that far, the Sun would be a star of magnitude 10.9: too faint for the eye, a target for binoculars.
- Naked eye, binoculars or telescope?
- The naked eye, even from a city: at magnitude 2.15 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Almach: Cih is 21° north-west of it, a spread hand at arm’s length.
Look for
From 50° north and 35° north it is circumpolar and never sets; from the equator it climbs to 29°; from 35° south it never rises.
Science
Cih’s surface is about 30,000 K, some 24,200 K hotter than the Sun’s 5,772 K, so its light is strongest at about 100 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 −4.0, brighter than Sirius, the brightest star in our sky.
Did you know
Against Almach, the brighter star the hop starts from: the two look about as bright as each other in our sky; Almach is 393 light-years away and Cih 549 light-years, so side by side Cih would give off 1.9 times as much light as Almach.
Science
Cih is the 134th nearest to us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is Mirfak, about 220 light-years from it; on our sky the two are 23° apart.
Look for
The Sun passes 49° south of Cih around early April, when it is highest at noon, in daylight: the weeks either side are its worst time of year. It is 2° from the plane of the Milky Way, inside the band a dark sky shows.