Star profile
Sadr
Gamma Cygni · Cygnus
Highly luminous starWhat is Sadr
Sadr sits at the very heart of Cygnus, where the cross the swan traces against the Milky Way meets itself. Its name comes from the Arabic «ṣadr al-dajājah», «the breast of the hen». A luminous F-class supergiant more than 1,800 light-years distant, it is wrapped in a dense, bright nebula of glowing dust well known to astrophotographers. The light reaching the eye tonight left its surface when the Roman Empire was still standing.
Where it is and when to see it
Sadr lies in the northern celestial hemisphere. It is visible to the naked eye under a dark sky. Its best month of the year is August, when it culminates around midnight.
- From London it never sets and culminates about 79° up.
- From New York it culminates about 90° above the horizon.
- From Sydney it culminates about 16° above the horizon.
It can be seen from anywhere north of 50° S.
It ranks no. 2 in brightness among the 137 stars of Cygnus in our catalogue. To find it, start from Deneb, the brightest: it lies about 6° away (a fist at arm's length covers about 10°).
The light you see today left it about 1,800 years ago.
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Astronomical data for Sadr
- Constellation
- Cygnus
- Apparent magnitude
- 2.23
- Distance
- 1832.6 light years
- Coordinates (J2000)
- RA 305.557° · Dec 40.257°
- Catalogue
- HIP 100453 · HD 194093
A symbolic commemorative gift: neither the signature nor the chosen name implies ownership of the star or recognition by the IAU.
Other stars in Cygnus
Cygnus has 137 stars in Stelvia's catalogue. Here are a few of them.
- DenebAlpha Cygni1.25
- AljanahEpsilon Cygni2.48
- FawarisDelta Cygni2.86
- AlbireoBeta 1 Cygni3.05
- Zeta Cygni3.21
- Xi Cygni3.72
- Tau Cygni3.74
- Iota 2 Cygni3.76