Blue-white subgiant · Grus

Alnair

Also known as: α Gruis (α Gru), HIP 109268

mag 1.7100 light-years

About

Alnair (α Gruis) is a blue-white subgiant of magnitude 1.7 in Grus, about 100 light-years away.

Alnair is in the constellation Grus.
Best evenings: around early October 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 south of 33° N.

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. It looks blue-white.
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	Alnair
Designation	α Gruis (α Gru)
Hipparcos number	HIP 109268
Type	Blue-white subgiant
Spectral type	B7IV
Colour	WhiteB−V colour index −0.07
Magnitude	1.7The smaller the number, the brighter.
Distance	100 light-yearsThe light you see left it around 1930.
Proper motion	0.20″ per year across the sky
Constellation	Grus
Right ascension (J2000)	22h 08m 13.9s
Declination (J2000)	−46° 57′ 40″