Star Stars · In Cygnus
Aljanah
Aljanah, ε Cygni, is an orange giant in Cygnus: the 93rd brightest star in the night sky.
Save the chart (SVG) Tactile chart (A4 SVG)
- Constellation
- Cygnus
- Designation
- ε Cygni
- Apparent magnitude
- 2.48 · 93rd brightest star in the night sky
- Spectral class
- K0III
- Distance
- 72.7 light-years
- Highest at midnight
- late July
- Position (J2000)
- RA 20h 46m · Dec +33° 58′
An orange giant, around 5,200 K, like Arcturus and Aldebaran. About 41× brighter than the faintest star the eye can see. Gives off about 42 times the Sun's visible light. The light you are seeing left in 1953.
When to see it
On the night of Sat 31 Jul 2027, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT+1 | 15:18 | 01:10 · 73° | 11:01 |
| New York EDT | 16:44 | 01:05 · 83° | 09:25 |
| Singapore GMT+8 | 19:12 | 01:15 · 57° | 07:18 |
| Sydney GMT+10 | 19:55 | 00:06 · 22° | 04:17 |
Common questions
- Can I see it from 50° north?
- Yes. It rises and sets, and at its highest it stands 74° up in the south.
- Can I see it from 35° south?
- Yes. It rises and sets, and at its highest it stands 21° up in the north.
- When is the best time of year to see it?
- Around late July, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by late October it is highest in the early evening, and in early May not until the hours before dawn.
- How far away is it, and how bright?
- It is 72.7 light-years away, and shines at magnitude 2.48 in our sky. From that far, the Sun would be a star of magnitude 6.6: one you would need a dark country sky to see at all.
- Naked eye, binoculars or telescope?
- The naked eye, even from a city: at magnitude 2.48 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Sadr: Aljanah is 7.9° south-east of it, a fist at arm’s length.
Look for
From 50° north it climbs to 74°; from 35° north it climbs to 89°; from the equator it climbs to 56°; from 35° south it climbs to 21°.
Science
Aljanah’s surface is about 5,200 K, some 600 K cooler than the Sun’s 5,772 K, so its light is strongest at about 560 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 0.7, about as bright as Altair looks to us.
Did you know
Against Sadr, the brighter star the hop starts from: Sadr looks 1.3 times as bright as Aljanah in our sky; Sadr is 1,832 light-years away and Aljanah 73 light-years, so side by side Sadr would give off 800 times as much light as Aljanah.
Science
Aljanah is the 28th nearest to us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is Alderamin, about 38 light-years from it; on our sky the two are 29° apart.
Look for
The Sun passes 49° south of Aljanah around late January, 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 19 hours a day, from 35° north about 16 and from 35° south about 8. It is 6° from the plane of the Milky Way, inside the band a dark sky shows.