Callippus was born at Cyzicus, and studied under Eudoxus of Cnidus at the Academy of Plato.
According to the description in Aristotle's Metaphysics (XII.8), he added two spheres for the Sun, two for the Moon, and one each for Mercury, Venus, and Mars.
He also followed up on the work done by Meton of Athens to measure the length of the year and construct an accurate lunisolar calendar.
Callippus started his observation cycle on the summer solstice in 330 BC (28 June in the proleptic Julian calendar).
The mechanism has a dial for the Callippic cycle and the 76 years are mentioned in the Greek text of the manual of this old device.