Transcript Presented by Dr. Frank Summers

Exploring the Universe with
Telescopes and Light
Dr. Frank Summers
Space Telescope Science Institute
December 5, 2008
How Telescopes Changed
Astronomy
Tycho Brahe
1546-1601
Galileo
1609 – First use
of telescope for
astronomy
Refracting Telescope
• Two glass lenses
• Long tube
• Refract – light bends
Yerkes 40 inch
1895
60 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
1845
72 inch mirror
54 feet long
Mount Palomar
1948
200 inch mirror
http://amazing-space.stsci.edu/resources/explorations/groundup/
http://amazing-space.stsci.edu
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
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International Society for Optical Engineering
Optical Society of America
National Optical Astronomy Observatory
National Science Foundation
• http://www.hands-on-optics.org
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
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
Spitzer
Hubble
Chandra
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
– [email protected]