Monthly Archives: October 2014

We are in the midst of a partial solar eclipse and there will not be one seen like this again until 2023.

What you see above is a simulation of the October 23, 2014 solar eclipse – at greatest eclipse (5:44 p.m. EDT) – from the vantage point of Canada’s Nunavut Territory near Prince of Wales Island. Notice that it is a partial eclipse. At greatest eclipse, from this prime location, the solar disk is 75% covered over by the moon. Everyplace else within the eclipse viewing area sees a shallower partial solar eclipse on October 23.

If you want to watch the eclipse directly, eye safety is of the utmost importance. That said, North America has a ringside seat to the partial eclipse of the sun on October 23. This eclipse is almost exclusively visible on land from North America.

SAFELY VIEW THE ECLIPSE

Permanent eye damage can result from looking at the disk of the Sun directly, or through a camera viewfinder, or with binoculars or a telescope even when only a thin crescent of the Sun or Baily’s Beads remain. The 1 percent of the Sun’s surface still visible is about 10,000 times brighter than the full moon. Staring at the Sun under such circumstances is like using a magnifying glass to focus sunlight onto tinder. The retina is delicate and irreplaceable. There is little or nothing a retinal surgeon will be able to do to help you. Never look at the Sun outside of the total phase of an eclipse unless you have adequate eye protection.

One safe way of enjoying the Sun during a partial eclipse–or anytime–is a “pinhole camera,” which allows you to view a projectedimage of the Sun. There are fancy pinhole cameras you can make out of cardboard boxes, but a perfectly adequate (and portable) version can be made out of two thin but stiff pieces of white cardboard. Punch a small clean pinhole in one piece of cardboard and let the sunlight fall through that hole onto the second piece of cardboard, which serves as a screen, held below it. An inverted image of the Sun is formed. To make the image larger, move the screen farther from the pinhole. To make the image brighter, move the screen closer to the pinhole. Do not make the pinhole wide or you will only have a shaft of sunlight rather than an image of the crescent Sun. Remember, this instrument is used with your back to the Sun. The sunlight passes over your shoulder, through the pinhole, and forms an image on the cardboard screen beneath it. Do not look through the pinhole at the Sun.

Did you see it? Have you seen one before?