1. Exploring the Universe with Telescopes & Light

2. Some Hands-On Optics

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

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

5. Simple Magnifiers Materials Always handle lenses by edges Thinner lens
Thicker lens
Astronomy picture
Always handle lenses by edges

6. Simple Magnifiers Hold a lens about an inch away from picture.
Move lens toward and away from picture.
Trade lenses and try it with other types of lenses.

7. Simple Magnifiers Which lens magnifies most?
At what distance does magnification cease?

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

10. Bends at each interface!

12. Lenses & Lasers & Lights
Materials
Various lenses
Various lasers
Bright image source
White paper
Always handle lenses by edges

13. Lenses & Lasers & Lights
Shine laser through various parts of a lens
Observe the change in refraction
Which part of the lens refracts more?
Shine two lasers or laser level through lens
Move lens toward and/or away from laser(s)
Can you get light points to converge?
Can you measure focal length of lens?

14. Lenses & Lasers & Lights
Line up a bright image source – lens – white paper
Try to project image onto white paper. It works best when paper is in shadow.
Adjust lens position to focus image.
Is image upright or inverted?
What is paper-lens distance? How does it compare to the lens focal length?

15. T

22. Hands-On Optics: Refracting Telescope I

23. Build a Refracting Telescope I
Materials
Thinner lens (20 cm focal length)
Thicker lens (7.5 cm focal length)
Always handle lenses by edges

24. Build a Refracting Telescope I
Hold the thinner lens in front of your eye with the thicker lens about a foot away. Examine a distant object by looking through both lenses.
Try the thicker lens in front of your eye with the thinner lens about a foot away.

25. Build a Refracting Telescope I
Which arrangement of lenses was easier to get a clear view?
Which arrangement of lenses magnified more?

30. Hands-On Optics: Refracting Telescope II

31. Build a Refracting Telescope II
Materials
Cardboard tubes (inner and outer)
Plastic bag of optics
Large lens
Small lens
Cardboard washer (disk)
Cardboard spacer (cylinder)
Plastic cap
Foam insert
Always handle lenses by edges

32. Build a Refracting Telescope II
How are these lenses different from the previous lenses?
Why are there two cardboard tubes?
Can a working telescope be built out of such simple materials?

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

34. Build a Refracting Telescope II
How is refraction different for a plano-convex lens than for a double convex lens?
What knowledge or skills would be important in making telescopes?
How might professional telescopes differ from these simple models?