Today Phil explains how telescopes work and offers up some astronomical shopping advice. Check out the Crash Course Astronomy solar system poster here: null -- Chapters: Introduction 00:00 How do Telescopes Work? 0:47 Refraction 2:50 Magnification 3:48 Resolution 4:28 Reflectors 5:19 What Kind of Telescope Should You Buy? 6:19 Technology and the Light Spectrum 7:45 Review 11:14 -- Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse -- PBS Digital Studios: null Follow Phil on Twitter: https://twitter.com/badastronomer Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse Want to find Crash Course elsewhere on the internet? Facebook - http://www.facebook.com/YouTubeCrashCourse Twitter - http://www.twitter.com/TheCrashCourse Instagram - https://www.instagram.com/thecrashcourse/ CC Kids: null -- PHOTOS/VIDEOS http://en.wikipedia.org/wiki/Galileo_Galilei#mediaviewer/File:Justus_Sustermans_-_Portrait_of_Galileo_Galilei,_1636.jpg http://en.wikipedia.org/wiki/Human_eye#mediaviewer/File:Human_eye_with_blood_vessels.jpg http://en.wikipedia.org/wiki/Refracting_telescope#mediaviewer/File:Refractor_Cincinnati_observatory.jpg http://commons.wikimedia.org/wiki/File:Positive_lens_2.svg http://www.eso.org/public/images/yb_vlt_moon_cnn_cc/ http://en.wikipedia.org/wiki/Jupiter#mediaviewer/File:Jupiter_MAD.jpg http://en.wikipedia.org/wiki/Wide_Field_and_Planetary_Camera#mediaviewer/File:Hubble_Images_of_M100_Before_and_After_Mirror_Repair_-_GPN-2002-000064.jpg http://commons.wikimedia.org/wiki/File:Prime_focus_telescope.svg http://commons.wikimedia.org/wiki/File:Inspection_of_the_primary_mirror_of_the_Hubble_Space_Telescope8218871.jpg https://www.youtube.com/watch?v=ui6ernRFxOg http://en.wikipedia.org/wiki/William_Herschel#mediaviewer/File:William_Herschel01.jpg http://commons.wikimedia.org/wiki/File:Grand_Canyon_National_Park,_23_Annual_Star_Party_2013_-_0082_-_Flickr_-_Grand_Canyon_NPS.jpg http://commons.wikimedia.org/wiki/File_talk:EM_spectrum.svg#mediaviewer/File:EM_spectrumrevised.png https://www.youtube.com/watch?v=RqX9vLj3_7w http://pprc.qmul.ac.uk/~still/wordpress/?page_id=138 http://en.wikipedia.org/wiki/VERITAS#mediaviewer/File:MMT_FLWO_Amado_AZ_10359.jpg http://en.wikipedia.org/wiki/Astrophotography#mediaviewer/File:Henry_Drape_Orion_nebula_1880_inverted.jpg http://en.wikipedia.org/wiki/Astrophotography#mediaviewer/File:Orion-Nebula_A_A_Common.jpg http://en.wikipedia.org/wiki/File:PIA18593-Mars-CometSidingSpring-NEOWISE-20140728.jpg http://en.wikipedia.org/wiki/File:NASA-HS201427a-HubbleUltraDeepField2014-20140603.jpg http://upload.wikimedia.org/wikipedia/commons/2/2b/Jupiter_and_its_shrunken_Great_Red_Spot.jpg http://upload.wikimedia.org/wikipedia/commons/thumb/5/58/Chromatic_aberration_3.svg/2000px-Chromatic_aberration_3.svg.png http://upload.wikimedia.org/wikipedia/commons/5/56/The_Whirlpool_Galaxy_%28M51%29.jpg http://hubblesite.org/newscenter/archive/releases/2005/12/image/a/