Alp-1

Its story

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.