As part of the zodiac, Capricorn has long been known in Babylon, although it represented a strange goat fish in these times. 2,500 years ago, the constellation contained the solstice point – the point where the Sun reaches the southernmost point on its apparent path across the sky. Although the solstice point is now to be found in the neighboring Sagittarius, the circle of latitude on the Earth over which the Sun is in the zenith during the winter solstice, is still called the „Tropic of Capricorn“.
The constellation itself is rather unremarkable. Johann Gottfried Galle observed in 1846 for the first time the planet Neptune in the vicinity of α Capricorni. Prior to his observation, Neptune’s position had been predicted by Adams and Leverrier based on disturbances in the motion of Saturn.
The 4.8m bright ρ Capricorni is an about 100 light-years distant star, which can easily be separated in binoculars as an optical double star. Four minutes of arc separate a 4.9 and a 6.6m bright star. The stars appear in yellow and purple.
M 30 has been described after its discovery in 1764 by Messier as „hardly visible nebula“. With 7.3m and a diameter of nine minutes of arc, this globular cluster is not a really obscure object, but especially at low magnification it can be easily outshone by the 21 arcmin distant star 41 Capricorni (5.2m). The horizon haze and the low position may complicate the observation additionally. Close to M 30 is another small star of eighth magnitude.