Friday, August 18, 2017

Windham Library to host Solar Eclipse Event by Walter Lunt

Astronomy buffs say the solar show will be less than spectacular, but worthwhile viewing

The moon over Maine will obscure less than 60 percent of the sun on Monday. And although darkening is expected to be minimal, local eclipse fans have made viewing plans at work, from home or at special gatherings.

The Windham Public Library will broadcast live streaming coverage (so to speak) of the solar eclipse for up to 50 people in the downstairs meeting room. Children’s room coordinator Diane Currier said the library’s Solar Eclipse Event will also feature information, activities and safe outdoor viewing of the partial eclipse, utilizing pinhole projections and protective solar eyeglasses. The event begins at 2 p.m.

Safe eclipse eyewear is a must for direct viewing. Most local stores are sold out, but Currier says most visitors to the library event will get to use and keep a pair of the solar glasses. eclipse of the sun occurs when the moon moves into a precise position between the earth and the sun, blocking its light. Even more phenomenal than the event itself is the fact that, at the time of eclipse, the diameter of the moon and the sun, as viewed from earth, is a virtual match. The result, as someone once put it, of sheer heavenly happenstance. 

The Great American Eclipse, as it’s being called, is unique in that it is centered only on the American continent. Totality will occur only in a narrow band, 67 miles wide, from Oregon to South Carolina. It will zoom across the country in 90 minutes. Latitudes north and south of the line will experience varying degrees of partiality. In the Portland area, 58.6 percent of the sun’s surface will be covered, resulting only in a slight dimming. That is, day will not become night and the stars will not come out, as in a total eclipse.

“The dimming will be slight, almost imperceptible,” according to Ed Gleason, Windham resident and director of the University of Maine’s Southworth Planetarium in Portland; who adds, “The planetarium will be open with live NASA feeds of the eclipse starting at 1:45 p.m. and, weather permitting, we will also have someone outside with a scope to enable people to observe the eclipse.”

The slow dimming of the sun, even during a partial eclipse, produces eerie daylighting, unlike the fading light caused by dark clouds passing in front of the sun. As described in a publication by Bill Nye (the science guy) recently, “Filtered sunlight creates alternating bands of light and dark on the ground – it’s otherworldly and spooky.” directly at the sun will damage eyes, possibly leading to blindness. The only safe way to view the eclipse is through special-purpose filters, such as eclipse glasses. Sunglasses or exposed photo film (negatives) are not safe.

Ron Thompson of Southern Maine Astronomical Group, who recently hosted a program on the eclipse at Windham Library said, “A solar eclipse is something you’ll never forget,” but went on to warn sternly and adamantly against watching it with the naked eye. Addressing both adults and children at the session, he added, “I don’t mean to scare you – but I do.” reviewed safe ways to view an eclipse, including watching it indirectly by constructing various pinhole devices and projecting the image onto a flat surface; #14 welders glass is safe. Other alternatives are solar telescopes and so-called sunoculars (specially filtered binoculars). On-line strategies for safe viewing can be accessed at eclipse.aas/ and 

Of recent concern is the sale of counterfeit, or fake, eclipse glasses. One way to test whether solar glasses are safe to use is to make sure they are stamped with an ISO certification label. In addition, the American Astronomical Society recommends an at-home test. They suggest looking through the special lenses – you should not be able to see anything except for the sun or anything significantly bright, like halogen or LED lights. Even those should look dim. Also, check for tears or scratches.
The best viewing time for Monday’s eclipse will be between 2 p.m. and 3 p.m. If you miss it, just wait for the next one . . . in 2024.

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