Blue-white main-sequence star · Scorpius

Acrab

Also known as: β¹ Scorpii (β¹ Sco), HIP 78820

mag 2.6400 light-years

About

Acrab (β¹ Scorpii) is a blue-white main-sequence star of magnitude 2.6 in Scorpius, about 400 light-years away.

Acrab is in the constellation Scorpius.
Best evenings: around early July 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 60° 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.
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	Acrab
Designation	β¹ Scorpii (β¹ Sco)
Hipparcos number	HIP 78820
Type	Blue-white main-sequence star
Spectral type	B0.5V
Colour	WhiteB−V colour index −0.07
Magnitude	2.6The smaller the number, the brighter.
Distance	400 light-yearsThe light you see left it around 1620.
Proper motion	0.026″ per year across the sky
Constellation	Scorpius
Right ascension (J2000)	16h 05m 26.2s
Declination (J2000)	−19° 48′ 20″