Caption: Tycho Brahe's (1546--1601) sky map for supernova SN 1572 (AKA Tycho) in constellation Cassiopeia.

Features:

1. In the sky map, you can sort of make out the Big W (i.e., Cassiopeia): trace letters F E D B G.

2. The labeled stars are:
   1. A: caput Cassiopea / ζ Cas.
   2. B: pectus Schedir / α Cas / Schedar.
   3. C: Cingulum / η Cas.
   4. D: lexura ad Ilia / γ Cas / Tsih / Navi.
   5. E: Genu / δ Cas / Ruchbah.
   6. F: Pes / ε Cas / Segin.
   7. G: suprema Cathedrae / β Cas / Caph.
   8. H: media Chatedrae / κ Cas.
   9. I: Nova Stella / SN 1572 / Tycho.

   Tycho did NOT generally use modern star names which mostly had NOT been decided on in his time. In particular, he had NO Bayer designations since Johann Bayer (1572--1625) was just getting around to being born in 1572.

3. SN 1572 was a Galactic supernova (i.e., it occurred in the Milky Way): the 3rd to last one known. There have probably been others since the last one (Cas A circa 1680, possibly observed by 1st Astronomer Royal John Flamsteed (1646--1719)), but they have been hidden by the interstellar dust in the galactic disk of the Milky Way.

4. SN 1572 was a SNe Ia and left no compact remnant (i.e., no neutron star or black hole), but there is an expanding supernova remnant. A binary companion to the supernova progenitor may be star Tycho G (see P. Ruiz-Lapuente et al. 2004).

5. Tycho did NOT discover SN 1572. It was a sudden bright new star (nova stella) and was commonly observed by anyone on Earth.

   But he did make detailed observations of SN 1572 and published a book on it which made him famous. The most important fact was that SN 1572 showed no parallax, and thus was beyond the Moon. Thus, SN 1572 violated the principle of Aristotelian cosmology that there could be no change beyond the Moon in the eternally-unchanging perfect Heavens.

   This violation of Aristotelian cosmology was one of the first pinpricks that would bring it down.

6. Note that Tycho wrote in Latin for the benefit of us who know not Danish. My rendering in English:
   The true distance to the star in fixed location in the hacker Cassiopeia the constellation by the exquisite instrumento of altogether minute capacity, locating Oberbayern. Ingeniously Antietam Cam distare ab ca, que eft in pectoral Schedar labeled B, 7 degrees, 55 arcminutes above verily.

   It loses something in the translation.