Related by context. Frequent words. (Click for all words.) 56 Perseid meteor shower 55 Perseids 54 total lunar eclipse 54 unaided eye 54 Halley Comet 53 comet 52 skywatchers 52 extrasolar planet 52 meteor shower 51 distant galaxy 51 gamma ray burst 50 Saturn rings 50 extrasolar planets 50 meteor showers 50 amateur astronomers 50 Orion Nebula 49 HD #b [002] 49 infrared telescope 49 Space Telescope 49 XMM Newton 49 total solar eclipse 48 galaxy cluster 48 optical telescopes 47 sunspot 47 comet nucleus 47 occultation 47 Aurora Borealis 47 Milky Way Galaxy 47 Hubble Telescope 47 aurora borealis 47 Phoenix lander 47 X ray emission 47 distant galaxies 46 Eta Carinae 46 planet orbiting 46 sunspots 46 cometary 46 stargazers 46 lunar eclipses 46 meteors 46 partial eclipse 46 aurora 46 lunar eclipse 46 NASA Cassini spacecraft 45 astronomers 45 comet dust 45 Cassini spacecraft 45 Betelgeuse 45 orbiting spacecraft 45 ringed planet 45 telescope 45 Saturn moons 45 exoplanets 45 Hubble telescope 45 supernova explosion 45 GRBs 45 auroras 45 infrared wavelengths 45 Spitzer Space Telescope 45 NASA Chandra 44 flyby 44 exoplanet 44 X ray Observatory 44 polar caps 44 planets orbiting 44 moon Titan 44 comet Wild 44 gamma ray bursts 44 quasars 44 NASA Mars Odyssey 44 MODIS 44 polar regions 44 Milky Way galaxy 44 partial solar eclipse 44 optical telescope 44 comets 43 NASA Aqua 43 Cassini orbiter 43 gravitational waves 43 amateur astronomer 43 meteor 43 sunrises 43 solar eclipse 43 brown dwarf 43 telescopes 43 geologically active 43 Mars Global Surveyor 43 contrail 43 THEMIS 43 dwarf galaxy 43 supernova 43 field Infrared Survey 43 coldest temperatures 43 nebulae 43 Hubble 43 interstellar dust 42 Mars Reconnaissance Orbiter 42 infrared radiation 42 Astronomers 42 MESSENGER 42 coldest