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(Click for frequent words.) 66 IBEX spacecraft 65 Orbiter MRO 65 Comet Hartley 65 Comet Hartley 2 64 NASA EPOXI mission 64 DISR 64 Orbiter LRO 63 Saturn Cassini 62 Spectrograph 62 NASA STEREO 62 imaging spectrometer 62 GALEX 62 Rosetta orbiter 62 ESO VLT 62 Observatory SDO 62 MESSENGER 62 VIRTIS 61 Planck satellite 61 Explorer WISE 61 Rosetta spacecraft 61 NASA Cassini spacecraft 61 gamma ray observatory 61 Galileo spacecraft 61 flyby spacecraft 61 ESA SMART 61 Mars Reconnaissance Orbiter MRO 61 hyperspectral imager 61 Solar Dynamics Observatory 61 spacecraft Cassini 61 Upsilon Andromedae 61 photometer 60 Relations Observatory STEREO 60 STEREO spacecraft 60 Cassini Huygens spacecraft 60 HiRISE camera aboard 60 asteroid Steins 60 NASA Stardust spacecraft 60 HiRISE camera 60 XMM Newton 60 Multi Object Spectrometer 60 Nasa Mars Reconnaissance 60 WISE infrared 60 Nasa spacecraft 60 SIRTF 60 flyby 60 Synthetic Aperture Radar SAR 59 NASA MESSENGER spacecraft 59 RXTE 59 Comet Lulin 59 Viking Lander 59 ESA Planck 59 X ray observatory 59 microscopic imager 59 Mars Orbiter 59 Churyumov Gerasimenko 59 Lunar Reconnaissance Orbiter LRO 59 WISE telescope 59 Solar TErrestrial RElations Observatory 59 Comet Halley 59 Convection Rotation 59 Mars CRISM 59 Aqua satellite 59 Voyager spacecraft 59 APXS 59 planetary Transits 59 spacecraft 59 Earth orbiting satellites 59 infrared imager 59 Pancam 59 WFC3 59 Near Infrared Camera 59 flyby Cassini 59 infrared telescopes 59 comet McNaught 58 Nasa Mars Odyssey 58 SOHO spacecraft 58 Context Camera 58 infrared observatory 58 NanoSail D 58 astrometric 58 Cassini 58 Moderate Resolution Imaging 58 orbiting Hubble Space Telescope 58 Mars Color Imager 58 Mercury flyby 58 retroreflector 58 MESSENGER spacecraft 58 fainter objects 58 Cassini flyby 58 Galaxy Evolution 58 Solar Orbiter 58 THEMIS 58 airglow 58 Ulysses spacecraft 58 Imaging Spectrometer 58 photometry 58 Heliospheric Observatory SOHO 58 OSIRIS 58 wavelength infrared 58 orbiting gamma ray 58 Comet Holmes 58 OMEGA instrument 58 Synthetic Aperture Radar 58 X ray Telescope XRT 58 Martian dust 58 NASA Interstellar Boundary 58 ESA XMM Newton 58 HiRISE 57 THEMIS Images 57 Diviner instrument 57 Mars Pathfinder lander 57 Saturnian moon Titan 57 Philae lander 57 EPOXI spacecraft 57 CoRoT satellite 57 Advanced Synthetic Aperture 57 orbiting observatory 57 stellar occultation 57 WMAP satellite 57 Stardust spacecraft 57 Planck spacecraft 57 Evolution Explorer 57 Hubble Space Telescope HST 57 radar altimeter 57 neutral mass spectrometer 57 Space Telescope 57 ray Space Telescope 57 XMM Newton satellite 57 moon Io 57 Block 5D 57 ESA Rosetta 57 NASA Stratospheric Observatory 57 rover panoramic 57 Herschel Space Telescope 57 cometary nucleus 57 Mars Orbiter Camera 57 Planck telescope 57 ESA Huygens probe 57 polarimetry 57 Mössbauer 57 highly elliptical orbits 57 VLTI 57 THEMIS spacecraft 57 aboard ESA Envisat 57 X ray telescopes 57 infrared wavelength 57 UVOT 57 ST5 57 New Horizons spacecraft 57 Mars landers 57 Deep Impact flyby spacecraft 57 Mars Pathfinder 56 spectrographs 56 comet nucleus 56 NuSTAR 56 WISE spacecraft 56 Heterodyne Instrument 56 ESA Proba 56 Viking orbiters 56 Viking landers 56 interstellar particles 56 Infrared Pathfinder Satellite 56 Planck 56 orbiting observatories 56 NASA Aqua 56 HD#b 56 Kepler Space Telescope 56 RHESSI 56 Infrared Mapping Spectrometer VIMS 56 Bug Nebula 56 Infrared Thermal Imaging Spectrometer 56 Uninhabited Aerial Vehicle 56 Kepler spacecraft 56 ultraviolet wavelengths 56 NASAs 56 Hubble observations 56 COROT 56 STEREO 56 NASA THEMIS 56 infrared wavelengths 56 spacecraft orbiting 56 Thermal Emission Spectrometer 56 Helioseismic 56 multispectral 56 Moderate Imaging Spectroradiometer 56 HRSC 56 Mars Reconnaissance Orbiter 56 innermost planet 56 Kuiper Belt Objects 56 asteroid Vesta 56 Keck Telescope 56 Descent Imager Spectral Radiometer 56 NFIRE satellite 56 polarimetric 56 Comet #P/Churyumov-Gerasimenko 56 Martian rovers 56 Multi Object Spectrograph 56 moon Charon 56 NASA LCROSS 56 Mission TRMM satellite 56 Ranging spacecraft 56 Fomalhaut b 56 EPOXI 56 NASA Lunar Reconnaissance 56 Deep Impact eXtended Investigation 56 NASA Wilkinson Microwave 56 Mini Thermal Emission 56 GOCE 56 Flyby 56 Cassini orbiter 56 Lunar Reconnaissance Orbiter Camera 56 spectroscopically 56 QWIP 56 submillimetre 56 Infrared Astronomy SOFIA 56 Mars moon Phobos 55 WFPC2 55 Kepler Mission 55 spectroscopic measurements 55 Messenger spacecraft 55 JWST 55 ESA Herschel 55 occultations 55 spectroscopic observations 55 Telescope BAT 55 Hubble Space Telescope 55 Sounder AIRS instrument 55 Interstellar Boundary Explorer 55 Imaging Spectroradiometer MODIS instrument 55 KAGUYA 55 GRB #B 55 O OREOS 55 CALIPSO 55 comet flyby 55 Mini TES 55 THEMIS satellites 55 Magnetic Imager HMI 55 LROC 55 NASA Cassini 55 High Resolution Imaging 55 P/# A2 55 solar corona 55 Shoemaker Levy 55 Composite Infrared Spectrometer 55 TRMM satellite 55 Faint Object 55 SMOS 55 GLAST 55 gamma ray spectrometer 55 robotic explorer 55 synthetic aperture radar 55 ESA Mars 55 Express orbiter 55 Planetary Camera 2 55 Cassini Huygens 55 CloudSat 55 Global Surveyor 55 laser altimeter 55 Wilkinson Microwave Anisotropy Probe 55 Fermi telescope 55 Hyakutake 55 Huygens lander 55 TerraSAR X 55 MERIS 55 exoplanetary 55 CRISM 55 Huygens mission 55 Microscopic Imager 55 Ranging MESSENGER spacecraft 55 NASA CloudSat 55 Antenna LISA 55 Comet Encke 55 Epsilon Aurigae 55 SIM PlanetQuest 55 Keck telescopes 55 Photometric Imaging Receiver 55 Comet 9P/Tempel 1 55 detect gravitational waves 55 intrinsic brightness 55 imager 55 infrared telescope 55 Tropical Rainfall Measuring 55 ESA Envisat 55 Ocean Salinity SMOS 55 infrared spectrograph 55 cometary 55 ESO PR 55 orbiting Mars 55 ultraviolet imaging spectrograph 55 Dynamics Observatory 55 Ring Nebula 55 impactor spacecraft 54 TanDEM X 54 NICMOS 54 radiometers 54 gaseous planet 54 Mars Odyssey spacecraft 54 stellar occultations 54 microshutters 54 unaided eye 54 IR wavelengths 54 FORCAST 54 BepiColombo 54 exoplanet hunter 54 spectrographic 54 supergiant star 54 Helix Nebula 54 TerraSAR X satellite 54 Great Observatories 54 spectroscope 54 NASA Atmospheric Infrared 54 orbiting spacecraft 54 orbiting Hubble telescope 54 Infrared Astronomy 54 STIS 54 spatially resolved 54 radio occultation 54 telescope eyepiece 54 KBOs 54 X ray wavelengths 54 comets orbiting 54 coronagraph 54 infrared spectra 54 Space Infrared Telescope 54 Planetary Transits 54 Spitzer infrared 54 SPIRE instrument 54 Viking Orbiter 54 Cassini spacecraft 54 Curiosity rover 54 VLBA 54 Interferometric 54 Panoramic Camera 54 solar radii 54 extrasolar planet 54 NASA ESA Hubble 54 Webb Telescope 54 Herschel telescope 54 submillimeter wavelengths 54 Reflection Radiometer 54 Sojourner rover 54 unmanned probes 54 SBSS satellite 54 spectroscopic analysis 54 Space Telescope GLAST 54 submillimeter 54 Solar Optical Telescope 54 adaptive optics 54 ESA ERS 54 outermost planets 54 ESA Integral 54 #P/Holmes 54 Robotic Arm Camera 54 orbiting telescopes 54 Jupiter flyby 54 Proba 2 54 Keck Interferometer 54 extrasolar 54 AKARI 54 NIRCam 54 twin Voyager spacecraft 54 NASA Far Ultraviolet 54 EPOXI mission 54 comet chaser 54 Titan flyby 54 hyperspectral 54 slender crescent 54 Resolution Stereo Camera 54 interferometry 54 Hubble 54 infrared spectrometer 54 Comet Machholz 54 asteroid Eros 54 spiral galaxy NGC 54 exosphere 54 periodic dimming 54 OGLE TR #b 54 ion propulsion 54 Mossbauer spectrometer 54 Mpc 54 Exoplanet 54 submillimetre wavelengths 54 Lunokhod 54 ROSAT 54 inch Samuel Oschin 54 Corot 7b 54 Adaptive optics 54 NASA Fermi Gamma 54 NOAA GOES 53 NASA Gamma ray 53 infrared astronomy 53 Saturn rings 53 smallest exoplanet 53 asteroid Lutetia 53 Observatory STEREO 53 Interferometer VLTI 53 MErcury Surface Space ENvironment 53 Spectroradiometer 53 infrared imagery 53 comet particles 53 scatterometer 53 HUDF 53 hyper spectral 53 arcsecond 53 multiwavelength 53 orbiter Mars Odyssey 53 Hubble Space 53 Quadrantid meteor shower 53 distant supernovae 53 telescope 53 MetOp 53 Impactor 53 Galilean moons 53 SPICAM 53 interplanetary spacecraft 53 millisecond pulsar 53 Epoxi 53 BLG #Lb 53 infrared spectrometers 53 Infrared Camera 53 gradiometer 53 visible wavelengths 53 Cloud Aerosol Lidar 53 galaxy M# [001] 53 #x magnification [002] 53 Cassini ion 53 Kuiper belt objects 53 CCD camera 53 constellation Aquarius 53 SPHERES 53 Hinode 53 electric ion propulsion 53 Rosette Nebula 53 Thermal Emission 53 Krimigis 53 ARGUS IS 53 equatorial orbit 53 Pleiades cluster 53 Hubble Telescope 53 astronomical objects 53 Kuiper Belt object 53 MG J# +# 53 astronomical telescope 53 Infrared Array Camera 53 NIRSpec 53 waning gibbous 53 Mars orbiter 53 Wilkinson Microwave Probe 53 LINEAR 53 Ultraviolet Imaging Spectrograph UVIS 53 arcsec 53 twin STEREO spacecraft 53 LCROSS spacecraft 53 Charon Pluto 53 telescopic observations 53 comet Hale Bopp 53 Moessbauer 53 sub millimeter wavelengths 53 XP# [004] 53 Anisotropy Probe WMAP 53 Multispectral 53 NASA Kepler telescope 53 ultraviolet spectrometer 53 CHARA 53 Space ENvironment GEochemistry 53 SINFONI 53 GOES O 53 Hubble telescope 53 coronal loops 53 X ray afterglow 53 Horizons spacecraft 53 supernova SN 53 millimeter wavelengths 53 Compact Reconnaissance Imaging Spectrometer 53 Fermi Gamma ray 53 EPOCh 53 Pluto Charon 53 X ray pulses 53 NASA Kepler 53 LRO spacecraft 53 Gamma ray Large 53 Synthetic Aperture 53 Hubble Near Infrared 53 moons orbiting 53 DIXI 53 Envisat Advanced Synthetic Aperture 53 #mm telephoto lens 53 Mars Descent Imager 53 infrared mapping spectrometer 53 Optical Spectroscopic 53 nightside 53 giant elliptical galaxy 53 X ray spectrometer 53 radiometer 53 spiral galaxy Messier 53 planet Gliese #g 52 radar altimeters 52 NASA MESSENGER 52 NASA Cosmic Background 52 pulsating aurora 52 Cancri e 52 widefield 52 Toutatis 52 infrared satellite imagery 52 Titan flybys 52 Global Surveyor spacecraft 52 Neutron Spectrometer 52 martian landscape 52 Cometary 52 Orbiter spacecraft 52 spacecraft flyby 52 Advanced Microwave Scanning 52 celestial sphere 52 MESSENGER MErcury Surface 52 Area Telescope LAT 52 NASA Lunar Crater 52 Mastcam 52 Total Ozone Mapping 52 Delfi C3 52 Opportunity rover 52 Delta Cephei 52 LADEE 52 LISA Pathfinder 52 detect gamma rays 52 infrared 52 IKAROS 52 FASTSAT 52 LRO 52 Dumbbell Nebula 52 substorm 52 Solar Dynamics 52 Gravity Probe B 52 noctilucent clouds 52 SpaceWeather.com 52 planetary nebulas 52 Hale Bopp 52 Investigation DIXI 52 SPIRE 52 Subaru telescope 52 Crab Pulsar 52 AMIE camera 52 DigitalGlobe WorldView 52 irregularly shaped asteroid 52 SECCHI 52 robotic lander 52 GLAST Burst Monitor 52 ultraviolet spectrograph 52 NASA Kepler spacecraft 52 Herschel Space 52 Stardust NExT 52 LCROSS 52 Orbital Express 52 Zeta Ophiuchi 52 NASA Mars Reconnaissance 52 Adaptive Optics 52 Mission SRTM 52 Advanced Spaceborne Thermal Emission 52 C1XS 52 orbiting telescope 52 NFIRE 52 shortwave infrared 52 interferometers 52 Saturn outermost moon 52 TRMM 52 FUV 52 waxing gibbous moon 52 GOES N 52 GJ #b [002] 52 extrasolar planet HD #b 52 Lunar CRater Observation 52 Cydonia region 52 Diviner 52 DEIMOS 52 constellation Carina 52 lobate scarps 52 Spectrometer 52 deconvolution 52 Martian terrain 52 Epsilon Eridani 52 comet Lulin 52 Orbiter 52 GEochemistry 52 Earthlike 52 sunlike star 52 Mossbauer 52 Servicing Mission 52 CoRoT 52 Proba 52 MARSIS 52 distant quasar 52 http:/saturn.jpl.nasa.gov 52 Deep Impact probe 52 spectro 52 Ultraviolet Optical Telescope 52 Crab Nebula 52 Stardust capsule 52 Mars Lander 52 Scatterometer 52 Submillimeter Array 52 Surveys ACS 52 Sensing Satellite LCROSS 52 celestial object 52 HiRISE images 52 star Spica 52 exoplanet 52 comet Hartley 2 52 ecliptic plane 52 Infrared Mapping Spectrometer 52 reflector telescope 52 proplyds 52 energetic electrons 52 ESA Envisat satellite 52 Sojourner Rover 52 spectrograph 52 binary asteroid 52 spacecraft Chandrayaan 1 52 orbital solitude 52 radial velocity 52 TacSat 52 globular cluster M# 52 optical wavelengths 52 #x# binoculars [001] 52 Extrasolar Planet Observation 52 Rosetta lander 52 Shepherding Spacecraft 52 Interior Laboratory GRAIL 52 Stephan Quintet 52 GRB# 52 STSS satellites 52 exoplanets planets 52 Raman spectrometer 52 astrometry 52 bolometers 52 RS Ophiuchi 52 speckle pattern 52 CALIPSO satellites 52 Moderate Resolution 52 highly elliptical orbit 52 Mars orbiting spacecraft 51 OGLE TR 51 Subaru Telescope 51 comet #P/Churyumov-Gerasimenko 51 gamma ray flares 51 WISE mapped 51 Samuel Oschin Telescope 51 Venusian surface 51 probe Chang'e 51 Mössbauer spectrometer 51 Flyby spacecraft 51 arcminutes 51 ChemCam 51 Facility SIRTF 51 JDEM 51 Titan Saturn 51 YES2 51 Field Imager 51 HARPS spectrograph attached 51 retrograde orbit 51 protoplanet 51 distant galaxies 51 Extreme Ultraviolet Imaging Spectrometer 51 interferometric 51 transiting planet 51 Lunar Crater 51 NASA rovers 51 astrophotographer 51 HiRISE image 51 optical microscopy 51 lunar orbiter Chang'e 51 scanning electron microscope SEM 51 UKIRT 51 AGNs 51 exoplanets orbiting 51 HEO payload 51 martian surface 51 gravitationally lensed 51 comet Churyumov Gerasimenko 51 visit http:/saturn.jpl.nasa.gov 51 faint galaxies 51 nebulae 51 Triangulum Galaxy 51 Resolution Imaging Spectrometer 51 moons Phobos 51 Jenniskens 51 Alpha Particle 51 planetary transits 51 Mimas 51 MODIS instrument 51 Saturn moon 51 lunar crust 51 spectrometer 51 Solar Terrestrial Relations 51 dimensional reconstructions 51 ESA SMOS 51 Butterfly Nebula 51 Space Telescopes 51 planetary surfaces 51 planet magnetosphere 51 asteroid Itokawa 51 spaceborne 51 Ringed Planet 51 RRATs 51 NEAR Shoemaker 51 Mars rovers 51 supergiant stars 51 planet Uranus 51 celestial objects 51 heatshield 51 Moon Mineralogy Mapper M3 51 Satellite GOES 51 Chodas 51 Neptune Uranus 51 Stratospheric Observatory 51 Chang'eI 51 ESO Very Large Telescope 51 Rosetta comet chaser 51 distant galaxy clusters 51 Earth magnetotail 51 Boethin 51 Lunar Orbiter 51 LOFAR 51 inch Schmidt Cassegrain 51 amateur skywatchers 51 Jupiter magnetosphere 51 SN #A 51 inch refractor 51 NASA rovers Spirit 51 neutron spectrometer 51 exo planets 51 Enceladus flybys 51 Wallops Island Va. 51 Orionids 51 gamma ray telescope 51 ion thrusters 51 galaxy NGC 51 F#W 51 Red Rectangle 51 icy moons 51 optical microscope 51 Mercury exosphere 51 impactor 51 telescope atop Mauna 51 ESO astronomer 51 Extrasolar Planet Search 51 comet Boethin 51 spacecraft orbited 51 field Infrared Survey 51 extrasolar planets 51 NASA Moon Mineralogy 51 swingby 51 Spitzer infrared spectrograph 51 lidar instrument 51 Geminga 51 Imaging Spectroradiometer 51 THEMIS Image 51 cometary debris 51 Martian surface 51 ESO telescope 51 Astrophysicists 51 ESA Cluster 51 Carey Lisse 51 panoramic camera 51 flybys 51 Saturn moon Mimas 51 Amateur astronomers 51 synchronous polar 51 Planetary Fourier Spectrometer PFS 51 Chajnantor plateau 51 Keck telescope 51 submillimeter wavelength 51 Jupiter Icy Moons 51 interferogram 51 GPS IIF 51 radial velocity measurements 51 laser pulses 51 situ measurements 51 orbits 51 Explorer GALEX 51 Spectrometers 51 arcseconds 51 LCROSS Lunar Crater Observation 51 radiotelescope 51 Gamma ray 51 HIP #b 51 Mars Opportunity rover 51 elongated orbits 51 Aurigae 51 Cryosat 51 distant galaxy 51 Satellites GOES 51 Heliospheric Observatory 51 cosmic cannibal 51 Saturn moons Titan 51 X ray telescope 51 Saturn moon Iapetus 51 orbiter 51 MARSIS radar 51 hydroxyl molecules 51 Io Europa 51 LRO LCROSS 51 comet 51 filamentary structure 51 inch refractor telescope 51 rover Opportunity 51 Gravitational lensing 51 Hubble Ultra 51 Earthlike planet 51 sunspot cluster 51 closest flyby 51 YU# 51 Mars rover 51 UVIS 51 THEMIS mission 50 NEAs 50 geo synchronous 50 robotic rovers 50 ESO telescopes 50 Deep Impact Spacecraft 50 Lunar Orbiter Laser Altimeter 50 helium atoms 50 sized planets orbiting 50 optical telescope 50 GIOVE B 50 multispectral camera 50 Halzen 50 Pegasi 50 Laser Interferometer Gravitational Wave 50 Gamma ray Burst 50 Martian landscape 50 Earthlike planets 50 Gravity Probe 50 reionization 50 Stardust NExT mission 50 distant quasars 50 RY Sagittarii 50 interferograms 50 backscattered 50 Lunar Excursion Module 50 infrared ultraviolet 50 GRB # 50 Clementine spacecraft 50 S/# [001] 50 NASA twin STEREO 50 NROL 50 NEOSSat 50 Lyman alpha 50 meter Keck telescope 50 fluorescence microscope 50 Envisat satellites 50 Mauna Kea Hawaii 50 lander 50 Resourcesat 2 50 deformable mirrors 50 lunar landers 50 Beta Pictoris b 50 radial velocity technique 50 Magnetospheric 50 Deep Impact spacecraft 50 Cassini flybys 50 multiband imaging photometer 50 Comet McNaught 50 Atmospheric Infrared Sounder AIRS 50 Halley comet 50 Machholz 50 Jupiter Ganymede 50 Saturn Enceladus 50 Orion Nebula 50 heliopause 50 EMCCD camera 50 Foton spacecraft 50 particle beam 50 NASA Solar Terrestrial 50 SeaWiFS 50 Field Planetary Camera 50 Comet #P 50 Martian crater 50 Infrared Telescope Facility 50 Burst Alert 50 Meteorological Satellite 50 NASA Voyager spacecraft 50 Hipparcos 50 orbit insertion 50 redshifted 50 NASA Stardust NExT 50 electron ion 50 SPACECRAFT 50 Nuclear Spectroscopic Telescope Array 50 MODIS 50 Measuring Mission TRMM 50 transiting exoplanet 50 lunar orbits 50 geosynchronous 50 NASA Cassini orbiter 50 Nasa Deep Impact 50 RISAT 50 orbiting Saturn 50 refurbished Hubble Space 50 Gerard Kuiper 50 GJ #b [001] 50 diffraction patterns 50 NASA Lunar Prospector 50 Earth Asteroid 50 thin crescent 50 EVLA 50 ESA Huygens 50 Saturnian moon 50 interferometric observations 50 blazar 50 cometary dust 50 interferometer 50 Comet Hale Bopp 50 Chilean Atacama Desert 50 Resolution Instrument 50 Atacama Large Millimeter submillimeter 50 Huygens descent 50 Galilean satellites 50 INMS 50 Kuiper belt object 50 Perseid meteor 50 Kepler Telescope 50 rovers Spirit 50 Lulin Observatory 50 geosynchronous satellites 50 spectroscopic 50 robotic spacecraft 50 gamma ray detectors 50 Neutral Mass Spectrometer 50 ENAs 50 N. Rathnasree 50 Saturn magnetosphere 50 Comet Churyumov Gerasimenko 50 planets orbits 50 infrared laser pulses 50 Cepheid variables 50 Radar ASAR instrument 50 electron diffraction 50 Great Orion Nebula 50 zodiacal light 50 SHARAD 50 Lunar Prospector 50 infrared interferometry 50 BP Psc 50 Digitized Sky Survey 50 extrasolar planetary systems 50 Spudis 50 Saturnian 50 NASA Goddard 50 Mercury magnetosphere 50 Huygens 50 BLG #L 50 obscuration 50 Imaging Spectroradiometer MODIS 50 UAVSAR 50 thermal infrared 50 Saturnian moons 50 Saturnian system 50 planet TrES 50 orbital insertion 50 AB Aurigae 50 orbiting 50 jovian 50 Orionid meteor shower 50 NASA Landsat 50 Very Large Telescope 50 comet Wild 50 linearly polarized 50 telescopic camera 50 astronomers 50 Exoplanets 50 Mars Global Surveyor 50 microquasar 50 nightglow 50 microlensing 50 Eric Becklin 50 SDSS II 50 YORP effect 50 comet tail 50 Huygens Probe 50 Arizona Steward Observatory 50 Comet Tempel 1 50 Herschel SPIRE 50 GQ Lupi 50 Earth asteroid Itokawa 50 Minotaur rocket 50 microlensing events 50 diffraction pattern 50 orbital velocity 50 Hubble Space Telescopes 50 inch refracting telescope 50 Mars Climate Sounder 50 http:/www.nasa.gov/cassini 50 celestial observations 50 HD #b [002] 50 Hubble Space telescope 50 Pleiades star 50 Envisat satellite 50 spectral measurements 50 Hubble orbits 50 proto galaxies