SN 1572

Last night of all,When yond same star that’s westward from the pole
Had made his course to illume that part of heaven
Where now it burns
--Bernardo, Hamlet, Act 1, Scene 1, introducing The Ghost



This is a NASA picture of an area in Cassiopeia.
The red circle visible in the upper left part of the image is SN 1572, often called "Tycho's Supernova." This remnant of the star explosion is named after the astronomer Tycho Brahe, although he was not the only person to observe and record the supernova.
When the supernova first appeared in November 1572, it was as bright as Venus and could be seen in the daytime. It is still visible with a telescope but not with the unaided eye as light is reflected from the debris that resulted from the explosion, first seen by Tycho and his contemporaries. This cloud of material is about 3,500 light-years away and 35 light-years across. It is being heated by radiation from young, hot stars within it, and the dust within the cloud radiates infrared light.

In England, Queen Elizabeth summoned the mathematician and astrologer Thomas Allen, "to have his advice about the new Star that appeared in the Cassiopeia to which he gave his Judgement very learnedly", as the antiquary John Aubrey recorded in his memoranda a century later.

In Ming dynasty China, the star became an issue between Zhang Juzheng and the young Wanli Emperor: in accordance with the cosmological tradition, the emperor was warned to consider his misbehavior, since the new star was interpreted as an evil omen.

SN1572 upset all of traditional cosmology as it introduced change in a presumed unchanging universe and tremendous size in what was thought to be an approachable and manageable existence.

Some have argued that this is the star discussed in Hamlet in the quote above, a quote that sets the scene for the appearance of the Ghost, and eventually family and social upheaval.

As an aside, conspiracy/trivia fans will be interested in some minutia surrounding the star as it involves the man who was Shakespeare:

In England, the mathematician Thomas Digges studied the "new star" and wrote a book about it. Digges dedicated his book to Edward de Vere's new father-in-law Lord Burghley. 

The relevant ancestors of Tycho Brahe are  Erik Rosenkrantz (1427-1503)  and  Sophie Gyldenstierne (+1477),  parents of  Kirstine Rosenkrantz  (+1509 )

At the time of the explosion, the Stratford Shakespeare would have been in his teens--although the explosion glowed for 16 more years.