Related by context. Frequent words. (Click for all words.) 75 telescopes 66 telescope 65 observatories 65 quasars 64 XMM Newton 63 Very Large Telescope 63 X ray Observatory 63 astronomers 62 infrared wavelengths 59 extrasolar planets 59 distant galaxies 59 pulsars 59 gamma ray bursts 58 gamma ray burst 58 spectrometers 57 galaxy clusters 57 redshift 57 NASA Chandra 57 Telescope 56 interferometer 56 Telescopes 56 galaxies 56 quasar 56 cosmic microwave background 56 Milky Way Galaxy 56 Spitzer Space Telescope 56 adaptive optics 56 distant galaxy 56 spectroscopic 55 rocky planets 55 globular clusters 55 Space Telescope 55 planets orbiting 55 galaxy cluster 55 brown dwarfs 55 supernovae 54 WMAP 54 gravitational waves 54 observatory 54 gamma ray 54 Milky Way galaxy 54 exoplanets 54 exoplanet 54 gamma rays 54 cosmologists 53 unaided eye 53 seismometers 53 Astronomers 53 seismographs 53 wavelengths 52 supernovas 52 cosmic ray 52 neutron stars 52 satellites 52 astrophysicists 52 spectrometer 52 dwarf galaxies 52 GPS satellites 52 cosmic rays 52 celestial objects 52 solar flares 52 astrophysical 52 infrared 51 spectroscopy 51 laser pulses 51 spectra 51 cosmic dust 51 astronomer 51 neutrinos 51 lidar 51 amateur astronomers 51 orbiting satellites 51 particle accelerators 51 supernova explosion 51 spectrograph 50 spiral galaxies 50 pulsar 50 spatial resolution 50 THEMIS 50 interstellar dust 50 Spectrometer 50 magnetic fields 50 orbiting spacecraft 50 planet orbiting 49 CMEs 49 imager 49 asteroids 49 Mars Reconnaissance Orbiter 49 HiRISE 49 Envisat 49 planets 49 NASA Cassini spacecraft 49 neutrino 49 Milky Way 49 GLAST 48 LIDAR 48 Gamma Ray 48 infrared radiation 48 neutron star 48 Astronomy 48 Radio Astronomy Observatory