Camera Obscura for observing a solar eclipse

Build with your children a “CAMERA OBSCURA” (a lensless lens)

  1. cut a rough rectangle in the format ca 40cm x 40cm (~ 16″ x 16″) from a cardboard (e.g. part of a shipping box) – accuracy is NOT required
  2. Approximately in the middle of the cardboard (or the carton piece) please cut a hole with roughly 10cm x 10cm (~ 4″ x 4″) edge length
  3. Place a layer of butterbread wrapping film made of sturdy aluminum (kitchen roll aluminum foil) over the hole with adhesive tape along the four sides of the hole. The aluminum foil should have at least 15cm x 15cm (~ 6″ x 6″) edge length so that it is significantly larger than the rectangular hole cut into the carton. Care is not necessary – no one looks directly into the sun by this arrangement !!
  4. In this sturdy aluminum foil you can pierce 50 to 100 holes with a pin within the 10 x 10 cm cutout – the holes should be randomly distributed
  5. Next(while outside in the sun) hold the cardboard with the aluminum foil over a white A4 (Letter) paper sheet – with the aluminum foil in about 30 to 40 centimeters distance to the white paper. Shade the sun with the 40 x 40 cm cardboard so that the light of the sun falls from the sky – through the punched holes in the alufoil – onto the white paper. Try to hold the white paper so that the cardboard box with the “perforated” aluminum foil and the white paper are arranged parallel to each other. This is all “free hand”. The distances between carton and white paper do not have to be strictly adhered to!
  6. What you see projected onto the white paper are up to a hundred “tiny little suns” – projected images of the sun with a diameter of only 5 to 7 millimeters. These appear perfectly round – just like a mini-sun. No one looks towards the sun!
  7. If then you continue using this self-made “emergency device for solar observation” during the eclipse as described above under 6, then any child looking only at the white paper can see the many “suns” during the duration of the eclipse look always “bitten off” in a different way! There are then no round suns anymore but a hundred small “sickles”. This is a completely cost-free natural experience, which we have already explained several times in past eclipse, in order to alleviate the panic in the country somewhat (happened in Germany 2015).

It is correct – this emergency device can not completely replace the direct view. However, it is ABSOLUTELY SAFE and FREE – no human being looks directly into the sun – or even comes into the temptation to do so. The attention is completely fixed on the ongoing play on the white paper! Every 10 minutes these hundred little sickles look different.

Posted in How To – build your own solar filter.

Leave a Reply

Your email address will not be published.