White giant · Ophiuchus

Rasalhague

Also known as: α Ophiuchi (α Oph), HIP 86032

mag 2.149 light-years

About

Rasalhague (α Ophiuchi) is a white giant of magnitude 2.1 in Ophiuchus, about 49 light-years away.

Rasalhague is in the constellation Ophiuchus.
Best evenings: around late 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 north of 67° S.

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	Rasalhague
Designation	α Ophiuchi (α Oph)
Hipparcos number	HIP 86032
Type	White giant
Spectral type	A5III
Colour	Yellowish whiteB−V colour index 0.15
Magnitude	2.1The smaller the number, the brighter.
Distance	49 light-yearsThe light you see left it around 1977.
Proper motion	0.25″ per year across the sky
Constellation	Ophiuchus
Right ascension (J2000)	17h 34m 56.1s
Declination (J2000)	+12° 33′ 36″