OBSERVING THE SUN
The following are guidelines only. There is no safe way to look at the Sun for a prolonged period of time.
First, and most important of all - never, ever look at the Sun using any form of binoculars or telescope. Looking at the Sun through a small telescope (or binoculars) will be an extremely painful experience that will probably leave you blind!! This has happened to people - So Do Not Do It! Using a medium to large telescope would result in a situation similar to cooking a fresh egg in a microwave oven. The remains of your eye would have to be surgically removed...
So how can you observe an eclipse in safety?
Before the Eclipse Starts
Using a small telescope, point it at the Sun and project the Sun's image onto a piece of white card held behind the eyepiece. This is how all astronomers do it unless they possess extremely specialised (and very expensive) equipment. This is the safest method there is (please note if the telescope is not small enough even this procedure may not work - it may wreck the scope! But YOU should be OK. At least you can buy another scope! YOU cannot buy eyes wholesale!). You will clearly see the Moon slowly advancing across the Sun's disk and you may even see some sunspots. -NB-Do not forget that at this point children should be encouraged to make a lot of noise to frighten the dragon away. This technique has always worked for all previous eclipses! No dragon has yet eaten the Sun!!
When the Sun is covered by more than 75% it is possible to use specialised glasses to look at the Sun. The Sun is considerably dimmer than normal and the glasses help to reduce harmful radiation. Always remember
Even with the glasses, do not stare at the Sun for more than a few seconds at a time
Only use glasses which carry identification showing they are suitable for looking directly at the Sun. These will be identified by having a CE safety mark and meeting the transmission requirements of 'scale 12-16 of EN 169/1992' or are 'Certified by BSI #0086 notified body HP2 4SQ'. Please note Brian Johnson of East Sussex County Council Trading Standards Service has drawn to our attention that the BSI postcode HP2 4SQ is not part of the BSI approval number! We thank Brian for this information. However it is perhaps sad that people think a postcode could be an approval number!
Do not use several layers of exposed colour negative film to look at the Sun. These allow harmful ultraviolet rays to enter the eye.
If you are further north in the U.K. than Torquay then you will not get a total eclipse. If you are in Torquay or somewhere else on the eclipse path then you can watch with your own eyes once the total eclipse has started. Once the eclipse has started you will no longer be able to see the surface of the Sun - that is why it is an eclipse! It is safe enough to look at the eclipsed sun and you will be able to see its outer atmosphere (called the corona). This eclipse (1999) has a duration of approximately two minutes.
One safe way to see the eclipse is by pinhole projection. Take a sheet of card and punch a small hole in the middle and hold it up at arm's length. Look at the shadow on the ground and you should see a small image of the sun projected on the ground within the card shadow.
During the Eclipse
If you want to look at the Sun when an eclipse is not happing, there are two different methods to do this (one is described below)
Through a Pinhole
Push a pin through the middle of a large piece of paper. Then, line it up with the sun (without looking at the sun through the hole or through any other methods (using the shadow cast by the paper could help). Place a piece of paper below your pinhole, where the Sun's image can be projected (line up the projection of the Sun with the paper). Then, try and make another hole in the paper and try to line the two projections produced onto the paper below.
The Sun can also be viewed through eyepiece projection and through filters attached to a telescope/binoculars (please do research on this if you want to observe the Sun in this way) . For more information on this and more on how to observe the Sun, please follow this link (a NASA guide), this link (Space.com's guide) and this link (Sky & telescope's guide).