Blue-white main-sequence star · Ursa Major

Alkaid

Also known as: η Ursae Majoris (η UMa), HIP 67301

mag 1.9100 light-years

About

Alkaid (η Ursae Majoris) is a blue-white main-sequence star of magnitude 1.9 in Ursa Major, about 100 light-years away.

Alkaid is in the constellation Ursa Major.
Best evenings: around early June 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 31° S.
Star patterns: Big Dipper.

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	Alkaid
Designation	η Ursae Majoris (η UMa)
Hipparcos number	HIP 67301
Type	Blue-white main-sequence star
Spectral type	B3V SB
Colour	WhiteB−V colour index −0.10
Magnitude	1.9The smaller the number, the brighter.
Distance	100 light-yearsThe light you see left it around 1920.
Proper motion	0.12″ per year across the sky
Constellation	Ursa Major
Right ascension (J2000)	13h 47m 32.5s
Declination (J2000)	+49° 18′ 48″