Exploring the Universe with Telescopes and Light Dr. Frank Summers Space Telescope Science Institute December 5, 2008

How Telescopes Changed Astronomy

Tycho Brahe

Galileo 1609 – First use of telescope for astronomy

Refracting Telescope Two glass lenses Long tube Refract – light bends

Yerkes 40 inch feet long

Telescope Qualities Resolution –See small things –Refractor - long tube Light Gathering –See faint things –Refractor - large lens

Isaac Newton 1668 reflecting telescope

Reflecting Telescope Mirrors to collect and focus light Lens as eyepiece Reflect –light bounces Shorter tube Larger mirrors

Herschel 7 foot 1780s 6.2 inch mirror

Leviathan inch mirror 54 feet long

Mount Palomar inch mirror

From Astrometry to Astronomy

Galileo 1610 Siderius Nuncius

Riccioli 1651

Galileo 1610

Messier 1774

Messier 1774

Draper 1882

Hubble 2006

Build a Refracting Telescope

Hands-On Optics Inquiry-based activities Collaboration –International Society for Optical Engineering –Optical Society of America –National Optical Astronomy Observatory –National Science Foundation

Hands-On Optics Terrific Telescopes –Selected three activities –Significantly abbreviated Module 3: Magnificent Magnifications –sciencefirst.com $475 classroom kit

Simple Magnifiers Materials –Thinner lens –Thicker lens –Astronomy picture Always handle lenses by edges Handout for reference

Simple Magnifiers 1.Hold a lens about an inch away from picture. 2.Move lens toward and away from picture. 3.Try it with the other type of lens.

Simple Magnifiers Which lens magnifies more? At what distance does magnification cease?

Simple Magnifiers Which lens magnifies more? At what distance does magnification cease? Thinner lens – 20 cm focal length Thicker lens – 7.5 cm focal length

Build a Refracting Telescope I Materials –Thinner lens (20 cm focal length) –Thicker lens (7.5 cm focal length) Always handle lenses by edges Handout for reference

Build a Refracting Telescope I 1.Hold the thinner lens in front of the thicker lens and examine a distant object. 2.Now try the thicker lens in front of the thinner lens. (This can be difficult.)

Build a Refracting Telescope III Materials –Cardboard tubes (inner and outer) –Plastic bag of optics Large lens Cardboard washer Cap Small lens Foam eyepiece holder Cardboard spacer Always handle lenses by edges Handout for reference

Build a Refracting Telescope III 1.Put curved side of large lens against end of outer tube. Add washer and cap. 2.Push small lens into foam eyepiece holder. 3.Slide cardboard spacer into foam eyepiece holder against the flat side of small lens. 4.Slide foam eyepiece holder into inner tube with cardboard spacer toward end.

Build a Refracting Telescope How does a plano-convex lens differ from a double convex lens? What knowledge or skills would be important in making telescopes? How might professional telescopes differ from these simple models?

Exploring with Light and Color

Exploring Visible Light

Where do the colors come from? What is the difference between light of different colors?

Exploring Visible Light

Exploring Emission Spectra Materials –Discharge tubes –Power supplies –Diffraction grating glasses Do not touch tubes or power supply –HIGH VOLTAGE Teacher Handout Student Handout

Exploring Emission Spectra 1.Observe the gas tube with your eyes. 2.Observe the gas tube through the diffraction glasses. 3.Repeat for other gas tubes.

Exploring Emission Spectra Where might astronomers see emission spectra? What information would an emission spectra provide?

Spectrum of the Sun – Type G2 Star

Spectrum of Arcturus – Type K1 Star

Spectrum of Procyon – Type F5 Star

The Universe Beyond Your Eyes

Hubble Space Telescope Spitzer Space Telescope Chandra X-ray Observatory

Chandra Hubble Spitzer Compton

How Light is Used as a Tool Materials –Electromagnetic spectrum poster Teacher Handout Student Handout

How Light is Used as a Tool 1.Identify a feature that is visible in several types of light. 2.Identify a feature that is visible in only one type of light.

How Light is Used as a Tool What do astronomers gain by observing the same object using different types of light? How might multi-wavelength observations affect specialization and collaboration in astronomy?

Myths vs Realities Handout Exploring with Light and Color –Full packet available –Bonnie Eisenhamer