© Reeth Informal Astronomy Group unless otherwise indicated

 Observing Safely

There are three ways to observe the eclipse safely: buy special eclipse glasses, build a pin-hole camera or use an astronomical telescope to project an image of the sun.

1. The simplest is to buy a pair of eclipse glasses – the Yorkshire based astronomy shop “Green Witch” are doing them for about £2.99 a pair, and some are being provided free with the Sky at Night magazine. But there are other sources – provided you order them in time. But wherever you get you eclipse glasses from, check that they are described as suitable for solar observation and check that they aren’t damaged before you use them – there should be no pin-holes or cracks which could allow the intense sunlight through.

2. The cheapest is to make a “pin-hole” camera.  One version is:

•  Cut a square hole about 10cm by 10cm in the middle of a large sheet of very stiff card or cardboard.
• Stick a piece of aluminium foil over the hole so it is as flat and tight as possible;
• Use a pin or a paper-clip to poke a very small circular hole in the foil.
• Fix a large sheet of white card or white paper to something reasonably heavy (so it won’t blow away if there is a wind).
• Put the large white sheet on the ground (it may help for this eclipse if you prop it up at an angle on something)
• Hold the first piece of card between the sun and the large white sheet so that the sun shines through the hole onto the white sheet. With a  bit of experimentation, you will find a position where the pin-hole projects an image of the sun onto the white sheet.
• Ideally, arrange thing so that most of the white sheet is being shaded by the pin-hole sheet while the image of the sun is shining on it.

Other versions can be found online.

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