How the eclipse will look in its early, middle and late stages How to observe the eclipse Observing an eclipse of the Sun can be very dangerous if you're not careful. We often underestimate the power of the Sun - following an eclipse in 1984, many people suffered from eye problems as a direct result. The important thing to remember is that just cutting down the light is not enough. There are ways of using telescopes and binoculars safely, but if you do not have these there are a few methods you can use. Filters Everyone seems to have heard of using smoked glass, but this is not now recommended because of the infrared problem.
Photographic filters come into the same category.
Welder's glass is suitable, as long as it is No 14 or darker. At one time, people used dense black and white negatives, but again this is no longer always ideal. Colour film and some modern black and white film, such as Ilford XP-1, use dyes rather than silver, and let through infrared. If you have overexposed and developed silver-based black and white film which is really dense, then observing through one or two thicknesses of the densest part may be adequate. Well-equipped amateur astronomers use specially made filters over the front of their telescopes, but these are expensive and are not easily available.