1. Pinhole Projection www.moonshadowmix.co.za www.eclipseafrica.org
Claire Flanagan

2. You need:
a light that has a shape
e.g. the Sun in eclipse
a pinhole – make one in a sheet of paper
using a sharp pencil
a screen – another sheet of paper

3. How it Works
remember: light travels in straight lines

4. The Sun is a disk of light for us on Earth

5. . . . sunlight shines in straight lines, in all directions

6. . . . sunlight shines in straight lines, in all directions
But if we limit the light
with a pinhole
we see something interesting . . .
. . . the shape of the Sun!

7. paper

8. hole
(any shape)

9. Sun
hole

10. Sun
hole
another paper

11. hole
sunlight

12. hole
sunlight
limited by hole

13. hole
patch of light
same shape as hole

14. If we make the hole smaller then no matter what the shape of the hole
we see the shape of the Sun
Watch
the green rays from one edge of the Sun and
the red rays from the other edge

15. big hole -> light spreads -> we see shape of hole

16. smaller hole -> light spreads less

17. small hole -> light from edge of the Sun is focused
-> we see shape of Sun
hole
image of the Sun

18. smaller hole = better focus (but less light = dimmer image)
image of the Sun

19. Experiment with different shapes and sizes of holes
big square
small square
small triangle
big triangle

20. small square
big square
small triangle
big triangle

21. different sizes of holes
Experiment with
different sizes of holes
bigger
smaller

22. bigger
smaller
better focus
brighter

23. further from the screen?
What if the pinhole is
further from the screen?
pinhole
screen

24. If the screen is further,
the image is bigger

25. The best pinhole projecters are gaps between the leaves of trees

26. Put a sheet of paper on the ground
to see images of the Sun

27. Taller trees give bigger images of the Sun

28. Pinhole-projected eclipse under a tree, Cape Town 2009
Photo: Simon Fishley

29. Write your name in pinholes, and photograph the projection
Photo: Astronomical Society of Southern Africa

30. Make pinhole gaps between your fingers . . .
Photo: Windell Oskay from Sunnyvale, CA, USA

31. . . . and watch the eclipse!
Photo: Windell Oskay from Sunnyvale, CA, USA

32. Next solar eclipses for SA . . .
Thu 1 Sep 2016
mid-morning
Sun 26 Feb 2017
late afternoon
Jhb
Cape Town