Sommers-Bausch Observatory at the University of Colorado at Boulder will host a special public open house on Friday, Dec. 14, between 1 p.m. and 4 p.m., to allow visitors to safely view a partial eclipse of the sun using the observatory's solar telescope.
According to Keith Gleason, a coordinator at the observatory, the moon will obscure 15 percent of the diameter of the sun at maximum eclipse, which occurs at 2:40 p.m. local time.
"The eclipse will begin at 1:53 p.m. - called 'first contact' - when the moon starts to take a bite out of the sun. The eclipse will end at 'last contact,' when the moon finishes passing in front of the sun and the disk of our star returns to full view at 3:26 p.m.," said Gleason.
Provided that the sky remains mostly free of clouds, visitors will be able to watch the moon move across the face of the sun during the 90-minute eclipse, and will be able to pick out the outlines of lunar craters seen in profile against the glare of the sun, said Gleason.
"Sunspots will be easy to see, and if we're lucky, visitors may also have the opportunity to observe a solar flare in progress during the event," he said. Finally, just as the eclipse ends, observers will be treated to a sun setting behind nearby Green Mountain.
Gleason warned that it is not safe for eclipse observers to attempt to view even a partial solar eclipse with the naked eye, or through photographic negative film or virtually any other filter. "Binoculars or telescopes that are not specifically designed and outfitted for viewing the sun also can be dangerous," he said. "Permanent eye damage can easily result from improper viewing techniques."
While there are several safe ways to view an eclipse, including pinhole camera arrangements and eyepiece projection techniques, the observatory encourages viewers to drop by instead during the open house to ensure that they are watching the eclipse in a manner that is safe.
The last partial solar eclipse visible from Colorado occurred on Christmas morning 2000, although few people reported seeing it because of cloud cover. The next solar eclipse will happen on June 10th.
Sommers-Bausch Observatory is located on the CU-Boulder campus, near the intersection of Regent Drive and Kittridge Loop. For directions and more information about the eclipse, visit the observatory web site at .