Star profile

Rukbat

Alpha Sagittarii · Sagittarius

Hot blue star

3D likeness based on its real data · class B · ~15,000 K

What is Rukbat

Rukbat takes the Arabic 'rukbah', 'knee', and indeed marks the knee of the archer in Sagittarius, just where the centaur figure braces to draw back the bow. Although it is the alpha of its constellation, it is not the brightest member of Sagittarius: traditional names do not always follow the modern hierarchy of brightness measured in magnitudes. It is a hot blue star some 182 light-years away, its light having crossed space since 1844.

Where it is and when to see it

Rukbat lies in the southern celestial hemisphere. It is visible to the naked eye under a dark sky. Its best month of the year is July, when it culminates around midnight.

From London it never rises above the horizon.
From New York it culminates about 9° above the horizon.
From Sydney it culminates about 83° above the horizon.

It can be seen from anywhere south of 49° N.

It ranks no. 16 in brightness among the 117 stars of Sagittarius in our catalogue. To find it, start from Kaus Australis, the brightest: it lies about 13° away (a fist at arm's length covers about 10°).

The light you see today left it about 180 years ago.

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Astronomical data for Rukbat

Constellation: Sagittarius
Apparent magnitude: 3.96
Distance: 181.8 light years
Coordinates (J2000): RA 290.972° · Dec -40.616°
Catalogue: HIP 95347 · HD 181869

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Other stars in Sagittarius

Sagittarius has 117 stars in Stelvia's catalogue. Here are a few of them.

See all 117 stars in Sagittarius