Red bright giant · Hercules

Rasalgethi

Also known as: α¹ Herculis (α¹ Her), HIP 84345

mag 2.8360 light-years

About

Rasalgethi (α¹ Herculis) is a red bright giant of magnitude 2.8 in Hercules, about 360 light-years away.

Rasalgethi is in the constellation Hercules.
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 66° 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	Rasalgethi
Designation	α¹ Herculis (α¹ Her)
Hipparcos number	HIP 84345
Type	Red bright giant
Spectral type	M5IIvar
Colour	Pale orangeB−V colour index 1.16
Magnitude	2.8The smaller the number, the brighter.
Distance	360 light-yearsThe light you see left it around 1670.
Proper motion	0.033″ per year across the sky
Constellation	Hercules
Right ascension (J2000)	17h 14m 38.9s
Declination (J2000)	+14° 23′ 25″

Star data: HYG Database by David Nash, CC BY-SA 4.0. All data sources →