April 2nd, 2008
While we’re waiting for our Solar Telescope to arrive, you might like to try making your own solar viewer… and if you think this sounds like fun, have a look at the animations made out of Galileo’s sunspot drawings of 1613, pictured above.
Warning: Do not look directly at the Sun under any circumstances or you will cause permanent and irreparable damage to your sight. You can, however, observe what is happening to the Sun through a solar viewer.
What you need
To build a solar viewer you will need:
* two pieces of white card
* aluminium foil
* a pin
* binoculars or telescope (optional).
What to do
1. Cut a five centimetre square in the centre of one piece of card.
2. Use a piece of aluminium foil to cover the square hole and tape to the card. Pierce a small hole in the centre of the foil using a pin or the sharp end of a pencil.
3. Stand with your back to the Sun and hold the card with aluminium foil above your shoulder or to your side, in the direction of the Sun. Use the other piece of cardboard to show the light passing through the hole in the aluminium foil.
4. By changing the distance between the two pieces of card you can change the size and brightness of the Sun’s image.
5. Holding the two pieces of card approximately one metre apart works best.
An alternative is to use a telescope or pair of binoculars to project an image of the Sun.
Diagram showing light from the Sun entering one lense of the binoculars and shining onto a screen as an image.
At no time should you look through the binoculars or telescope to view the Sun.
If you use binoculars attach them to a tripod and cover one lens with a piece of card.
Aim the binoculars or telescope at the Sun and project the image on to a screen or wall.
To protect the binoculars or telescope from becoming hot and overheating, turn it away from the Sun every minute or so.