Red giant · Ophiuchus

Yed Prior

Also known as: δ Ophiuchi (δ Oph), HIP 79593

mag 2.7170 light-years

About

Yed Prior (δ Ophiuchi) is a red giant of magnitude 2.7 in Ophiuchus, about 170 light-years away.

Yed Prior is in the constellation Ophiuchus.
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 76° 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	Yed Prior
Designation	δ Ophiuchi (δ Oph)
Hipparcos number	HIP 79593
Type	Red giant
Spectral type	M1III
Colour	Orange-redB−V colour index 1.58
Magnitude	2.7The smaller the number, the brighter.
Distance	170 light-yearsThe light you see left it around 1860.
Proper motion	0.15″ per year across the sky
Constellation	Ophiuchus
Right ascension (J2000)	16h 14m 20.7s
Declination (J2000)	−03° 41′ 39″