Tycho Brahe (Martian crater) the karge Kepler, nearly northeast is Electris Mons. Tycho Brahe (Martian crater) Tycho Brahe is a nearly ovular crater on Mars named after the Danish astronomer Tycho Brahe (1546–1601). It is located in the Cerberus hemisphere around 49.8° south and 213.9° west, in an area which is south of the Martz crater and east of the Hellas Basin. It measures approximately 105 kilometers in diameter from east to west. The name was adopted by IAU's Working Group for Planetary System Nomenclature in 1973. The crater is crossed by Eridania Scopulus, an escarpment. Other nearby named craters are Huggins to the
Planetary nebula the French astronomer Antoine Darquier de Pellepoix described in his observations of the Ring Nebula, "...a very dim but perfectly outlined; it is as large as Jupiter and resembles a fading planet". Whatever the true origin of the term, the label "planetary nebula" became ingrained in the terminology used by astronomers to categorize these types of nebulae, and is still used by astronomers today. Most planetary nebulae form at the end of the star's life, and are a relatively short-lived phenomenon, lasting perhaps a few tens of thousands of years, compared to a typical stellar lifetime spanning several billion years.