On Wednesday, 2009 July 22, a total eclipse of the Sun is visible within a narrow corridor of the Earth. People in Taiwan can observe a partial solar eclipse.  They should not attempt to observe it with the naked eye. Failure to use appropriate protection may result in permanent eye damage or even blindness.  Many incidents exist on record where people suffered such eye damage by looking at the Sun with improper methods or instruments.  Proper precaution can prevent unfortunate accidents.

The safest method to observe solar eclipse is by projection, in which a pinhole or small opening is used to cast the image of the Sun on a screen placed a half-meter or more beyond the opening.  Many people can then observe the image on the screen.

It is possible to observe a solar eclipse directly with properly protected eyes.  It is best to select professional eclipse glasses and use it under the supervision of experienced teachers or astronomy experts.  Those who have any form of eye disease or have undergone eye surgery should never look directly to the sun, even with professional eclipse glasses.

People who use paper eclipse glasses should pay special attention to the following advice: (1) They should look for as short a time as possible -- a few seconds at most -- per viewing of the Sun. (2) Parents should watch carefully how their children use the glasses. Because of the heavy light filtration, the pupils will be dilated when wearing the glasses. Taking them off for even a brief moment to look at a partially dimmed sun can prove disastrous. (3) Under no circumstance should anyone remove the glasses to get a "better look" at the Moon superimposed on top of the Sun.  (4) Users should dispose of the glasses as soon as the eclipse is over and not save them for later use as light leaks could develop over time from various kinds of stress.

A solar eclipse, partial or total, is a rare astronomical phenomenon which is well worth observing. We recommend the experience to everyone -- as long as they do it SAFELY!

References:

http://eclipse.gsfc.nasa.gov/SEhelp/safety.html

http://www.exploratorium.edu/eclipse/how.html