27 September 2020 10:32 PM

How to observe the Sun and be safe

Monday، 20 July 2009 12:00 AM

How to observe the Sun and be safe eclipse in Egypt

The safest way to observe the Sun, and watch the progress of the partial phase of the eclipse, is to not look directly at the Sun at all. Instead, project the Sun’s image onto a piece of white paper, using a pinhole camera . Binoculars may also be used to project the Sun’s image; they need to be supported on a tripod, one lens should be covered, and a sheet of white paper held behind the eyepiece. Focus the binoculars to achieve a sharp image.

Do not look directly at the Sun through the binoculars! To observe the Sun safely before and during the partial phase of the eclipse, most of its light and its harmful ultraviolet and infrared rays must be filtered out. Safe filters include:

Using two layers of fully exposed and developed black-and- white film (color film will not provide adequate protection).

Using a special metal-coated piece of plastic, typically aluminized Mylar, certified for viewing the Sun. Double-sided coatings greatly reduce the possibility of filter defects.

Rectangular welder’s glass, shade No. 14. Less dense shades (lower numbers) are not suitable for direct solar observation. Welder’s glass will also produce a green-colored image.
Many filters that are sometimes recommended for observing the Sun are not safe for direct-eye viewing, including a piece of glass blackened by soot from a candle, sunglasses, photographic neutral-density filters, and solar filters that operate at the eyepiece of telescopes or binoculars. Eyepiece filters are especially dangerous; they are placed at the point where the Sun’s light is most concentrated and magnified. They can crack or even explode.

So when the next total eclipse of the Sun rolls around at march 2006 , just remember a few rules:

1. It’s OK to look at the totally-eclipsed Sun with the naked eye - but only when the Sun is totally covered by the Moon, so you have to pick the right moment;

2. Never look at the partially-eclipsed Sun with the naked eye. Even a slim crescent has enough energy to blind you;

3. It’s safe to look at the fully-exposed or partially-exposed Sun with approved filters, such as professional Solar Viewing Mylar filters. But never look directly at the Sun with smoked glass, exposed photographic films, or Mylar food packaging.

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