Solar Projector

Introduction

There are periodic astronomical events that could never be observed by any human alive today. One of these was the transit of Venus on 8^th June 2004.

On 8^th June 2004 almost half of th inhabitants on Earth were able to watch the tiny black dot of the planet Venus moving across the disc of the sun. The weather that day was absolutely perfect and there was not a cloud in the sky over London and Kent. The whole thing took about 6 hours starting at approximately 5.20am and ending 11.23am.

WARNING

Never observe the Sun with the naked eye or a telescope, camera or other optical device. Doing so will seriously damage your eye sight and may lead to permanent blindness . Both the eye and artificial optical devices concentrate the extremely strong ultraviolet light from the Sun onto the retina. This can permanently destroy the retina's ability to detect light. To safely observe the Transit of Venus you must use the Kitchen Table Sciencemethod outlined below.

The Challenge

To create a Solar Projector that is able to view the Sun safely

Constraints

£0.00

Items used

2 x Large Cardboard Box
2 Compact Discs
Glue
Sharp Pin
1 Sheet A3 paper
Duct Tape
Sunshine!

Build Time

10 minutes

Method

Projector

There was no science in this one, I simply went up to the skip outside the office and found a cardboard box which had a base surface equal to that of an A3 piece of paper, Any size will do it just needed tall sides to act as a shade. Glue a fresh, clean piece of white A3 print paper to the inside base.

The Pinhole

Simply take an old CD, I usually just use and old installation disc. Itis pretty obvious that the central hole of A CD is way to large so a little innovation is required.

Take a large pair of scissors and just cut another old CD until you get a nice shard small large enough to cover the central hole of the other CD. Take this shard and very carefully stick a ppin through it. This can take a little while and don't be temted to use heat or a hammer. Just work away, patiently and carefully. The smaller and cleaner the hole, the cleaner the image will be at the end.

Simply glue the shard over the hole trying to make the pinhole as central as possible similar to the image on the left

Making the pinhole

Nothing could be simpler; Get a large cardboard box, the largest you can find and open it up until you get a flat sheet of card board.

Roughly in the centre of the cardboard sheet make a hole about 2.5 cm or 1 inch in diameter and then glue the CD pingole to the cardbaord making sure the pinhole is in the centre of the new hole. I used super glue throughout for speed.

Set up

All you need now is a friend or colleague place the cardboard box at an angle roughly perpendicular to the sun and then place the pinhole in between the sun and the box and move it backwards and forwards until the sun comes into focus......It is a bit fiddly but it is well worth the trouble..See the results below.

The Results

Click each image to get a lager view

Magic Forest

The Venus Transit 2004