Orange giant · Serpens

Unukalhai

Also known as: α Serpentis (α Ser), HIP 77070

mag 2.674 light-years

About

Unukalhai (α Serpentis) is an orange giant of magnitude 2.6 in Serpens, about 74 light-years away.

Unukalhai is in the constellation Serpens.
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 north of 74° 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	Unukalhai
Designation	α Serpentis (α Ser)
Hipparcos number	HIP 77070
Type	Orange giant
Spectral type	K2III
Colour	Pale orangeB−V colour index 1.17
Magnitude	2.6The smaller the number, the brighter.
Distance	74 light-yearsThe light you see left it around 1952.
Proper motion	0.14″ per year across the sky
Constellation	Serpens
Right ascension (J2000)	15h 44m 16.1s
Declination (J2000)	+06° 25′ 32″

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