White subgiant · Aquila

Altair

Also known as: α Aquilae (α Aql), HIP 97649

mag 0.817 light-years

About

Altair (α Aquilae) is a white subgiant of magnitude 0.8 in Aquila, about 17 light-years away.

Altair is in the constellation Aquila.
Best evenings: around early 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 71° S.
Star patterns: Summer Triangle.

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.

EyesA first-magnitude star, obvious even from a city.
Binoculars (10×50)Dazzling, with its colour stronger than to the eye.
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	Altair
Designation	α Aquilae (α Aql)
Hipparcos number	HIP 97649
Type	White subgiant
Spectral type	A7IV-V
Colour	Yellowish whiteB−V colour index 0.22
Magnitude	0.8The smaller the number, the brighter.
Distance	17 light-yearsThe light you see left it around 2009.
Proper motion	0.66″ per year across the sky
Constellation	Aquila
Right ascension (J2000)	19h 50m 47.0s
Declination (J2000)	+08° 52′ 06″