Was Shakespeare's use of "retrograde" an astronomical metaphor?

In Hamlet (I.2) Claudius remarks to Hamlet that his plan to return to university at Wittenberg is

... most retrograde to our desire ...

To a modern ear, this is striking and poetic, but I wonder:

• Was this use of "retrograde" an explicit (and perhaps unusual) astronomical or astrological metaphor, or was it then common to use the word to mean opposed to or against?
• If not an explicit metaphor, would its use have had astronomical or astrological overtones?

Solution 1:

TL;DR: Shakespeare likely intended at least a loose allusion to the astronomical sense of the word retrograde, and could have expected (some of) his audience to pick up on this connotation.

The OED lists some non-astronomical uses of retrograde back to the early 1500s, chiefly meaning "backward" in one sense or another. ("retrograde, adj., n., and adv." OED Online. Oxford University Press, September 2016.) However, the Hamlet quote, dated to approximately 1616, is the earliest attestation for the meaning "Opposed, contrary, or contradictory to something." (Definition 5.) This may be a case of Shakespeare stretching a word's meaning (which wouldn't be surprising) or it could just be that earlier similar uses aren't recorded, but it seems likely that this meaning wasn't the primary understanding for the word.

As to whether the term would have been recognized as having astronomical/astrological connotations, I think the answer is probably yes, at least for a significant chunk of the audience.

One modern scholar has actually argued that Hamlet is rife with astronomical references, and can be read as an allegory for the debate between geo-centrism and helio-centrism (Peter Usher, "Hamlet and Infinite Universe", 1997).

I don't know that I would go that far, but other scholars have also pointed out examples of Shakespeare's references to astronomy/astrology, as in this 1964 Irish Astronomical Journal article by W.G. Guthrie and this 2008 article by Michael Rowan-Robinson of the Imperial College London. As the examples in these articles illustrate, Shakespeare made reference to comets, meridians, poles, and the progress of the stars, just for starters.

There is also evidence that astronomy and astrology would have been somewhat familiar to at least some members of Shakespeare's audience. For example, Queen Elizabeth had recourse to a Court Astronomer/astrologer, John Dee ("John Dee", Wikipedia).

And it is not just royal and noble members of the audience who might have caught these references; the records of an earlier astrologer suggest that "he had a wide range of clients, from all walks of life, and indicates that engagement with astrology in 15th-century England was not confined to those within learned, theological or political circles." ("History of Astrology", Wikipedia, citing Sophie Page, 'Richard Trewythian and the Uses of Astrology in Late Medieval England', Journal of the Warburg and Courtauld Institutes Vol. 64, (2001), pp. 193-228.) It is possible that this widespread engagement with astrology would have declined in the decades between Trewythian and Shakespeare, but at least among the literate part of the populace interest remained high enough to create a market for William Lilly's books on astrology well into the seventeenth century. ("William Lilly", Wikipedia)

So I think it is at least plausible that Shakespeare used the word retrograde with an understanding of its astronomical or astrological sense, and with the possibility in mind that a sizable portion of his audience would also be aware of this sense.

Solution 2:

In Hamlet, "retrograde" has the negative connotation of Hamlet returning to the university in Wittenberg, using the conceit of a planet undergoing retrograde motion. This latter meaning is the case since retrograde motion for superior planets occurs when planets are in Opposition to the Sun, and in Hamlet the word "opposition" precedes the word "retrograde" by 14 lines or so. Of course the second meaning of the royal couple "opposing" Hamlet's return to Wittenberg also obtains. See my Shakespeare and the Dawn of Modern Science, pp. 84-5.

"Retrograde motion" also occurs in All's Well in connection with the motion during battle of the cowardly warrior Parolles. See my Shakespeare and Saturn: Accounting for Appearances pp. 73-4.