The Bard of Avon, unlike Chaucer, Dante, or Milton, seldom made use of astronomy or astrology. He never employed horoscopes, for example, to emphasize the traits of his characters. For all his numerous writings there are but few references, such lines as
There's not the smallest orb which thou behold'st But in his motion like a angel sings, (Merchant of Venice, V.i)
The fault, dear Brutus, is not in our stars, but in ourselves. (Julius Caesar, I.ii)
Saturn and Venus this year in conjunction! What says th' almanac to that? (2 Henry IV, II.iv)
The exhalations whizzing the air Give so much light that I may read by them. (Julius Caesar, II.i)
Since the Greeks thought that comets were exhalations of the atmosphere, this latter passage shows that Shakespeare was erudite enough to know this fact.
However, in Act III, Scene 1, the Bard is guilty of a great blunder. Caesar says:
But I am as constant as the northern star,
Of whose true-fix'd and resting quality
There is no fellow in the firmament.
The skies are painted with unnumber'd sparks,
They are all fire and every one doth shine,
But there's but one in all doth hold his place:
Now, in Shakespeare's time, Polaris was about 2 degrees from the north celestial pole, close enough to appear fixed. But since Julius Caesar is speaking in 44 BC, some 1650 years before Shakespeare put the words into his mouth, Polaris was at that time 10 degrees from the pole and could not have been considered as fixed. In Caesar's time, both Polaris and Beta Ursae Majoris described circles of 10 degree radius.
Therefore, one concludes that Shakespeare did not know anything about precession, though Hipparchus had discovered the phenomenon in the first century BC.
Hamilton Amateur Astronomers
Maintained by Grant Dixon