Related by context. Frequent words. (Click for all words.) 59 observatory 57 telescope 56 Lowell Observatory 56 infrared telescope 55 optical telescope 54 ESO Very Large Telescope 54 WM Keck Observatory 53 Griffith Observatory 53 telescopes 53 astronomer 53 Palomar Mountain 52 Observatory 52 astronomers 51 Space Telescope 51 optical telescopes 51 Very Large Telescope 51 Telescope 51 XMM Newton 51 Eta Carinae 51 planetary scientist 51 NASA Cassini spacecraft 50 extrasolar planets 50 adaptive optics 50 Jet Propulsion Laboratory 50 infrared wavelengths 49 NASA Chandra 49 Hubble telescope 49 Spitzer Space Telescope 49 Observatories 48 IceCube 48 Orion Nebula 48 Perseid meteor shower 48 planet orbiting 48 NASA Jet Propulsion Laboratory 47 optical microscope 47 extrasolar planet 47 JWST 47 Hubble Space Telescope 47 Mars Reconnaissance Orbiter 47 observatories 47 transmission electron microscope 47 Cassini spacecraft 47 Hubble 46 Cassini 46 Caltech 46 Hubble Telescope 46 Saturn rings 46 Milky Way Galaxy 46 rover Opportunity 46 Geysers 46 dwarf galaxy 46 X ray emission 46 NASA Ames 46 CloudSat 46 HiRISE 46 Earth asteroids 46 astronomy 46 field Infrared Survey 46 Smithsonian Astrophysical Observatory 46 THEMIS 46 NASA Mars Reconnaissance 45 supernova explosion 45 Mono Lake 45 National Ignition Facility 45 Technology Caltech 45 Astronomy 45 distant galaxy 45 NASA Goddard 45 scanning electron microscope 45 unmanned spacecraft 45 moon Titan 45 quasars 45 distant galaxies 45 Adler Planetarium 45 celestial objects 45 planetary science 45 amateur astronomer 45 HD #b [002] 45 meteor shower 45 Malin Space 45 panoramic camera 45 El Capitan 45 unaided eye 45 spectroscopic 44 Solar System 44 X ray Observatory 44 Exploratorium 44 Perseids 44 San Andreas Fault 44 Space Telescope Science 44 comet 44 Planetary Laboratory 44 Betelgeuse 44 Astronomers 44 comet nucleus 44 galaxy cluster 44 infrared spectrometer 44 astrophysicists 44 auroras 44 Kilauea volcano 44 SETI Institute