Blue-white giant · Cepheus

Alfirk

Also known as: β Cephei (β Cep), HIP 106032

mag 3.2690 light-years

About

Alfirk (β Cephei) is a blue-white giant of magnitude 3.2 in Cepheus, about 690 light-years away.

Alfirk is in the constellation Cepheus.
Best evenings: around late September 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 9° 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.

EyesVisible from the suburbs on a clear night, but lost in bright city skies.
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	Alfirk
Designation	β Cephei (β Cep)
Hipparcos number	HIP 106032
Type	Blue-white giant
Spectral type	B2IIIv SB
Colour	Blue-whiteB−V colour index −0.20
Magnitude	3.2The smaller the number, the brighter.
Distance	690 light-yearsThe light you see left it around 1340.
Proper motion	0.015″ per year across the sky
Constellation	Cepheus
Right ascension (J2000)	21h 28m 39.6s
Declination (J2000)	+70° 33′ 39″