post DIY Solar Viewer

April 2nd, 2008

Filed under: Cosmos — newseditor @ 9:32 pm


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

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.

Source: CSIRO


  1. My goodness this is a most terrific experiment for young and old, not sure about those in between. The principles explained herewith are those of the original ‘camera obscura’ used by 19thC landscape painters to cheat but of course the joke was on them…the resultant image was upside down!…meaning after painting their picture they would need to physically turn it around the other way or else be found out for cheating with this device. This was the origins of the silver halide bromide photographic plate.

    likewise for users of this technique if you can find a large tarpaulin and make a hole to fit the device (as described above) you can watch the sun with improved clarity in the dark or paint an upside down landscape or portrait back the front.

    In relation to the sun that the ‘sunspots’ from our perspective move from left to right…taking 13 days…so if you notice a sunspot to the right of the image its a newly emerged sunspot.

    Marvelous to see projects that were common place in my early days seeing the light of day again.


    Comment by Caldwell — April 3, 2008 @ 9:26 am

  2. Thank you for this information, we are going to build one with Dad on the weekend.
    We have made a volcano and will get some photos in very soon.
    Siobhan, Morgaine and Fionn N.

    ps we are going to check out the animations now, we will let you
    know about it later.

    hi siobhan, morgaine and fionn, have fun and let us know if you see any sunspots. looking forward to seeing that volcano! – amt

    Comment by Siobhan, Morgaine & Fionn — April 3, 2008 @ 5:57 pm

  3. Possum, our sheep ate our pictures! We have to start again.
    Siobhan, Morgaine & Fionn

    Comment by Siobhan, Morgaine & Fionn — April 13, 2008 @ 3:02 pm

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