Related by context. Frequent words. (Click for all words.) 56 telescope 56 observatory 55 planetarium 54 astronomical observatory 54 telescopes 53 camera obscura 52 Lick Observatory 51 scanning electron microscope 51 Palomar Observatory 51 astrophotography 51 sundials 50 optical telescope 50 photometer 49 astronomy 49 Keck Observatory 49 interplanetary spacecraft 49 geodesic 49 STScI 49 adaptive optics 48 Hubble Telescope 48 ESO Very Large Telescope 48 Observatories 48 pinhole camera 48 whale skeleton 48 astronomical objects 48 Olympus Mons 48 optical telescopes 47 particle detectors 47 Pan STARRS 47 photometry 47 spectrographs 47 astronomer 47 astronomical observations 47 Planetarium 47 extrasolar planet 47 Telescopes 47 infrared telescope 46 WM Keck Observatory 46 Orion Nebula 46 Lowell Observatory 46 Corot 46 Southern Observatory ESO 46 geodesic domes 46 astrophysical 46 nebulae 46 Crab Nebula 46 Amateur astronomers 46 Astrophysicist 46 Stained glass 46 Valles Marineris 46 stereoscope 46 astrophysicist 46 interferometric 45 XMM Newton 45 sundial 45 celestial object 45 Griffith Observatory 45 astronomers 45 constellation Orion 45 amateur astronomer 45 microscopes 45 CfA 45 Fresnel lens 45 Advanced Photon Source 45 Andromeda galaxy 45 Astrophysicists 45 HiRISE camera 45 SPIRE 45 Astronomer 45 planet Uranus 45 OSIRIS 45 electron microscope 45 whirligigs 45 Aurora Borealis 44 Earthlike 44 scanning tunneling microscope 44 observatories 44 microlensing 44 stargazer 44 Edwin Hubble 44 Galaxy Evolution 44 LSST 44 interferometer 44 Adaptive Optics 44 NASA Cassini 44 optical wavelengths 44 X ray telescope 44 IceCube 44 Cassini imaging 44 Hubble telescope 44 Observatory 44 Adler Planetarium 44 NASA ESA Hubble 44 Saturn rings 44 Mauna Kea Hawaii 44 pinhole cameras 44 spectrograph 44 radial velocity 44 distant galaxy 44 astrophysics 44 Telescope