Star profile

Alpha 1 Capricorni

3D likeness based on its real data · class G · ~5,500 K

What is Alpha 1 Capricorni

Alpha-1 Capricorni, called Algedi Prima in medieval Arabic, marks one tip of the horn of the celestial Sea Goat. At 569 light-years, it is a yellow G-type giant, and together with its neighbour Alpha-2 it forms a perfect optical pair, separable by the unaided eye —not gravitational companions but a chance alignment that already intrigued Greek astronomers. The true distance between them is enormous, even if in the sky they almost touch.

Where it is and when to see it

Alpha 1 Capricorni 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 culminates about 26° above the horizon.
From New York it culminates about 37° above the horizon.
From Sydney it culminates about 69° above the horizon.

It can be seen from anywhere south of 77° N.

It ranks no. 10 in brightness among the 48 stars of Capricornus in our catalogue. To find it, start from Deneb Algedi, the brightest: it lies about 22° away (a fist at arm's length covers about 10°).

The light you see today left it about 570 years ago.

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Astronomical data for Alpha 1 Capricorni

Constellation: Capricornus
Apparent magnitude: 4.30
Distance: 569.3 light years
Coordinates (J2000): RA 304.412° · Dec -12.508°
Catalogue: HIP 100027 · HD 192876

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Other stars in Capricornus

Capricornus has 48 stars in Stelvia's catalogue. Here are a few of them.

See all 48 stars in Capricornus