Yellow-white supergiant · Cygnus

Sadr

Also known as: γ Cygni (γ Cyg), HIP 100453

mag 2.21,800 light-years

About

Sadr (γ Cygni) is a yellow-white supergiant of magnitude 2.2 in Cygnus, about 1,800 light-years away.

Sadr is in the constellation Cygnus.
Best evenings: around mid-September it is highest at about 9 pm (10 pm in summer time); a month earlier, two hours later.
Where on Earth: it is seen well, at least 10° up, from north of 40° S.
Star patterns: Northern Cross.

When it rises and sets tonight, how high it climbs and how much the Moon gets in the way are worked out in your browser for your place.

EyesEasy, even from town.
Binoculars (10×50)A sharp point; binoculars bring out its colour and the fainter stars around it.
Telescope (6–8 inch)Still a point of light at any magnification — stars are too far away to show a disc. Low in the sky, bright stars twinkle and flash colours.

Stars look the same in any instrument: brighter and sharper, but never bigger.

Proper name	Sadr
Designation	γ Cygni (γ Cyg)
Hipparcos number	HIP 100453
Type	Yellow-white supergiant
Spectral type	F8Ib
Colour	YellowB−V colour index 0.67
Magnitude	2.2The smaller the number, the brighter.
Distance	1,800 light-yearsThe light you see left it around AD 200. Distances this large are uncertain by 10% or more.
Proper motion	0.003″ per year across the sky
Constellation	Cygnus
Right ascension (J2000)	20h 22m 13.7s
Declination (J2000)	+40° 15′ 24″