H205 Cosmic Origins  Telescopes (Ch. 6)  Visit Kirkwood Obs  Time for Reflection  Hand in EP1 APOD

Beginnings… This sketch of a telescope was included in a letter written by Giovanpattista della Porta in August 1609

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 from lenses… to mirrors

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

in 6-8 meter telescopes WIYN TECHNOLOGY

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)

6.5-meter Telescopes Magellan Telescopes Twin 6.5-m in Chile Borosilicate honeycomb mirrors 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

Detecting the Light 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) 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 Photographic plates chemically stores data to record fainter light Very inefficient: only 4% of the light recorded on film

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???

UH-88”, Courtesy W.Brandner, 0.65” seeing 4’ 40” 5” >220 stars in 5”x5” Gemini N/Hokupa’a-QUIRC (U of H/NSF) The Power of Adaptive Optics

text The importance of image quality typical ground- based image Hubble image WIYN image The Ring Nebula

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 Bigger than a football field! Lasers will produce artificial stars in the sky to help focus starlight

8.4-meters Triple-fold optical design 3 billion pixel-camera 30,000 gigabytes each night LSST Large-aperture Synoptic Survey Telescope  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 vs. Ground- Based Observatories 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

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? When can I see Hubble? Where is the Hubble Space Telescope?

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”)

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 !!!