Never look directly at the Sun with your eyes or through a telescope, binocular or any other optical aid!
Looking directly at the Sun is extremely harmful to the human eye; when you look at the Sun with your unprotected eyes you are damaging your eyes in a manner similar to burning paper or tree leaves by focusing Sunrays with a magnifying lens.
Looking directly at the Sun can cause a retinal burn (damage) or seriously affect eyesight.
It may even cause total blindness: the amount of retinal damage depends on the amount of time during which the retina is exposed to the Sun.
The retinal burn is a wound that does not cause pain! The observer does not feel pain while his retina is being burned by solar radiation, and the symptoms only begin to appear hours after the observations, by then it is too late to go to a doctor.
If you look at the Sun through the normal telescope or binoculars, the situation is even much more dangerous to the human eye: the lenses of the telescopes and binoculars intensify the effects of the heat and light coming from the Sun.
The Sun (during eclipses or in normal conditions) can be observed ONLY with certain conventional methods and taking the necessary precautions explained in the section "Safe Eclipse Viewing". These conventional methods aim to safely view the Sun with adequate protection of the eyes of the observer.
Never look directly at the Sun during the partial or annular phases of any type of solar eclipses!
Although in partial and annular solar eclipses some portion of the Sun is obscured and the total brightness of the Sun is reduced, the intensity of the rays of the Sun remains unaffected and very harmful to the human eye.
Even if up to 99% of the disk of the Sun is eclipsed, the remaining 1% of the solar disk is still as harmful to the human eye as ever!
Only during the brief totality phase of a total solar eclipse the TOTALLY eclipsed Sun can be viewed safely with the unprotected eye.
The observer should know precisely when totality ends in order to protect his eyes before the Sun reappears again.
Never observe directly any other solar phenomenon, e.g., the transits of the planets Venus and Mercury.
Unfortunately, every year there are several cases of people who suffer retinal burns because of looking directly at the Sun without protecting their eyes.
In Egypt , some people suffered retinal burns as they viewed the total solar eclipse of 11 August 1999 (which was partial in Egypt ) without protecting their eyes.
There are even recorded cases of people who lost eyesight because of staring at partial eclipses of the Sun.
A solar eclipse is a fascinating experience that is not to be missed. To learn how to observe a solar eclipse safely, please read the section "Safe Eclipse Viewing".