Related by context. Frequent words. (Click for all words.) 64 constellation Leo 64 ecliptic 63 constellation Orion 62 X ray emission 62 constellation Perseus 60 occultation 60 supernova remnant 60 Kuiper belt 60 HD #b [002] 59 Saturn rings 59 aurora 59 planetary nebula 59 visible wavelengths 59 distant galaxy 58 Geminids 58 infrared wavelengths 58 Eta Carinae 58 ringed planet 58 Andromeda galaxy 58 Andromeda Galaxy 58 unaided eye 58 Leonid meteor shower 58 umbra 57 extrasolar planet 57 Crab Nebula 57 nebula 57 moonrise 57 planet orbiting 56 cosmic microwave background 56 microlensing 56 spiral galaxy 56 auroral 56 annular eclipse 56 Jupiter moons 56 reddish color 56 Orion Nebula 56 accretion disk 56 ejecta 55 NASA Cassini spacecraft 55 Fomalhaut 55 elliptical galaxies 55 torus 55 gravitational lensing 55 ellipse 55 galaxy cluster 55 planet orbits 55 Perseid meteor shower 55 Saturn moon Enceladus 55 globular cluster 55 magnetar 55 Voyager spacecraft 55 Gamma ray bursts 54 celestial object 54 nebulae 54 astronomical objects 54 Gliese #g 54 tiger stripes 54 Milky Way Galaxy 54 perigee 54 interstellar dust 54 Opportunity rover 54 rocky planets 54 solar nebula 54 Saturn moons 54 equinoxes 54 COROT 54 moon Titan 54 supermoon 53 GRBs 53 Milky Way galaxy 53 supernova explosion 53 heliosphere 53 sunspot 53 Cancri 53 iridescence 53 wispy clouds 53 Perseids 53 THEMIS 53 gamma ray burst 53 Spitzer Space Telescope 53 sunspot cycle 53 Meridiani 53 Leonids 53 substorms 53 cirrus clouds 53 XMM Newton 53 observable universe 53 Iapetus 53 contrail 53 astronomical observations 53 ionized gas 53 meteoroid 52 Mimas 52 scarps 52 supernova remnants 52 galaxy formation 52 Enceladus 52 constellations 52 spiral galaxies 52 supernova 52 comet nucleus