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H205 Cosmic Origins APOD Telescopes (Ch. 6) Visit Kirkwood Obs Time for Reflection Hand in EP1 This sketch of a telescope was included in a letter written by Giovanpattista della Porta in August 1609 Beginnings… Thomas Harriet’s Drawings of the Moon and Sun Technology moves forward… Telescopes get BIGGER Think about a square telescope… Round ones work the same way The amount of light a telescope collects increases as the area of the primary mirror (the square of the diameter) Telescopes and how they work to mirrors from lenses… Kirkwood Observatory • 12” refracting telescope (uses lenses to form an image) • Built in 1901 • Used for public outreach and teaching The 3.5-meter WIYN telescope Kitt Peak, Arizona The WIYN Telescope • Mirror: 3.5 meter diameter • Located at Kitt Peak, Arizona • Built in 1995 • IU has a share New Telescope Technology • • “Fast” mirror • Lightweight mirror Mirror shape controlled • Mechanically simpler mount • Temperature control Casting the WIYN Mirror Polishing the WIYN Mirror The WIYN New Technology “Dome” • • • • Compact telescope chamber Open for ventilation Insulated to keep cool Heated spaces kept separate WIYN TECHNOLOGY in 6-8 meter telescopes 8-10 Meter Telescopes Today • Keck Telescopes Gemini North and South • ESO’s Very Large Telescope • Subaru • Hobby-Eberly Telescope and SALT • MMT Observatory • Magellan • Large Binocular Telescope The Twin Keck Telescopes on Mauna Kea • Two 10-meter telescopes • “segmented” mirrors – 36 hexagonal segments • Keck I in 1993; Keck II in 1996 ESO’s VLT Cerro Paranal, Chile Four 8.2 meter telescopes – – – – Antu (the Sun) Kueyen (the Moon) Melipel (the Southern Cross) Yepun (Venus - as evening star) Magellan Telescopes Twin 6.5-m in Chile Borosilicate honeycomb mirrors 6.5-meter Telescopes MMT Observatory 6.5-m Telescope also borosilicate honeycomb located in southern Arizona Large Binocular Telescope Twin 8.4-meter mirrors on a single mount in southern Arizona Going Observing • To observe at a major observatory, an astronomer must: – Submit a proposal – Plan ahead – Work day and night • Astronomers may also “observe” via the Internet – Space observatories – Data archives – Remote observing – We will do this! Computers • Operating a computer and being able to program are as important as knowing how to use a telescope • Computers accomplish several tasks: – Solve equations – Move telescopes and feed information to detectors – Convert data into useful form – Communicate and distribute data The Human Eye Once used with a telescope to record observations or make sketches Not good at detecting faint light, even with the 10-meter Keck telescopes Detecting the Light •Photographic plates chemically stores data to record fainter light •Very inefficient: only 4% of the light recorded on film • Electronic Detectors – Incoming light strikes an array of semiconductor pixels that are coupled to a computer – Efficiencies of 95% are possible – CCD (Charged-coupled Device) Correcting for the Earth’s Atmosphere • Even at wavelengths where the atmosphere is transparent, the atmosphere “blurrs” light – Why to stars “twinkle” (scintillation)? – The condition of the sky for viewing is referred to as seeing – Distorted seeing can be improved by adaptive optics Adaptive Optics – Correcting distortions caused by the Earth’s Atmosphere How does it work??? The Power of Adaptive Optics 40” 4’ 5” >220 stars in 5”x5” UH-88”, Courtesy W.Brandner, 0.65” seeing Gemini N/Hokupa’a-QUIRC (U of H/NSF) The importance of image quality • text typical groundbased image Hubble image The Ring Nebula WIYN image New Telescopes to Answer New Questions • • • • 20 and 30-meter telescopes 8-meter survey telescope James Webb Space Telescope Virtual Observatory Adaptive Optics will be a key component of 20 and 30 meter telescopes Lasers will produce artificial stars in the sky to help focus starlight Large-aperture Synoptic Survey Telescope • • • • 8.4-meters Triple-fold optical design 3 billion pixel-camera 30,000 gigabytes each night LSST Survey the sky each week Real-time data analysis 3 billion sources + transients Beyond 30-meters ESO’s Overwhelmingly Large Telescope How much do big telescopes cost? Cost increases rapidly as the diameter increases Light Pollution • artificial lighting threatens all observatories on the ground • shield all outdoor lights Electromagnetic Spectrum Is the Atmosphere Transparent or Opaque? Applets\light_absorption.swf Observing at Nonvisible Wavelengths • Astronomical objects radiate in wavelengths other than visible (thermal radiators) – Cold gas clouds – Dust clouds – Hot gases around black holes • Telescopes for each wavelength region – – – – Require their own unique design All collect and focus radiation and resolve details False-color pictures to show images Some wavelengths must be observed from space Radio Telescopes • Radio telescopes work the same way as optical telescopes • Large metal “mirror” reflects radio waves • Space-Based Advantages – Freedom from atmospheric blurring – Observe at wavelengths not transmitted by air • Ground-Based Advantages – Larger collecting power – Equipment easily fixed • Ground-Based Problems – Weather, humidity, and haze – Light pollution Space vs. GroundBased Observatories Exploring New Wavelengths: Gamma Rays • 1967 gamma-ray bursts from space discovered by military satellites watching for Soviet nuclear bomb explosions • Source of gamma-ray bursts is now (almost) understood • Gamma rays from Milky Way center and remnants of exploded stars Space Telescopes • NASA’s four Great Observatories – – – – Visible – Hubble Space Telescope Gamma rays - Compton Gamma Ray Obs. X-rays - Chandra X-ray Observatory Infrared - Spitzer Space Telescope The Hubble Space Telescope Hubble Trivia • Launched April 24, 1990, by Space Shuttle Discovery • Visible light, ultraviolet, and near-infrared • Orbits about 380 miles (611 km) above Earth • About the size of a bus • Primary mirror ~ 2 meters • Named after astronomer Edwin Hubble – discovered galaxies beyond our Milky Way – determined that space is expanding Keeping track of Hubble • Where is Hubble now? Where is the Hubble Space Telescope? • When can I see Hubble? www.heavens-above.com Space and Ground in Partnership • Supernova brightness measured with Hubble • Distances measured from the ground The Chandra X-Ray Telescope How Do X-Ray Telescopes Work? • • • • X-rays do not reflect off mirrors the same way that visible light does X-ray photons penetrate into the mirror in much the same way that bullets slam into a wall X-rays ricochet off mirrors like bullets off a wall X-ray telescopes are very different from optical telescopes. X-ray mirrors are precisely shaped and aligned to incoming x-rays. They look more like barrels than the familiar dish mirrors of optical telescopes. The Spitzer Infrared Space Telescope Spitzer Trivia • • • • Launched 25 August 2003 Estimated Lifetime:2.5 – 5 years Orbits the Sun, Earth-trailing, heliocentric Telescope – only 85 cm diameter (33.5”) www.spitzer.caltech.edu/about/now.shtml Compton Gamma Ray Observatory • 1991 – 2000 • solar flares • gamma-ray bursts • pulsars • nova • supernova explosions • black holes • quasar emission What does it cost????? • Proposed NASA budget for 2009: ~$18 B – Science – – – – ~$5.3 billion * Exploration ~$5.0 billion Aeronautics ~$0.7 billion Space Ops ~$7 billion Education ~$0.15 billion *All astronomy research and space telescopes are in this part. Comparable Spending • • • • • • • • $20 billion at jewelry stores (US) $24 billion at liquor stores (US) $40 billion on weight loss (US) $23.5 billion on candy and gum (US) $31 billion on pet toys and supplies (US) $7 billion on video rentals (US) $18 billion on makeup (worldwide) $35 billion on bottled water (worldwide) Great Observatories’ Costs • • • • Hubble Space Telescope: $6 billion Chandra X-ray Telescope: $2.5 billion Spitzer IR Telescope: $1.2 billion Compton Gamma Ray Tel: $0.56 billion Question: Why does society chose to support science research at this cost? For Week 2: Chapter 23 (Origin of Universe) Chapter 4 (Gravity) EP 2 Special Lecture: Tuesday, March 24, FA015, 7:30 PM The Chemical Heritage of Star and Planet Formation Good for Reflection 1 !!!