TUSCALOOSA, Ala. That’s not Santa Claus that will pass between the Earth and the sun and block out portions of sunlight on Christmas Day, it’s the moon, and University of Alabama astronomers invite the public to come to campus and safely view the partial solar eclipse on Monday, Dec. 25.
The public can come to UA’s Gallalee Hall from 9:45 a.m. until 1 p.m. on Christmas Day and see, weather permitting, how a telescope can be used to project the image of the eclipse to allow safe viewing.
“You should not look directly at the sun, and you should not use that new telescope you just got for Christmas to look at the sun unless it is equipped with the proper filter,” said Dr. William Keel, a UA professor of astronomy.
Some filters are safer than others, Keel said. Aiming the telescope’s lens at the sun, without looking through it, and allowing it to project the image through the eyepiece onto a white piece of paper is much safer than using an inexpensive filter that might not offer adequate protection, he said. Small eyepiece filters can sometimes overheat and crack without warning, Keel said.
Simple devices, such as a cardboard box and a piece of paper, can be used to safely project the image. Allowing the sun’s light to shine through your overlapped fingers and onto a white object, such as a piece of paper or even your white tennis shoes, beneath them will also work, Keel said.
The sun’s rays are no more harmful during an eclipse than during typical daylight, but Keel said the temptation to look at the sun is greater during an eclipse. The moon passing between the Earth and the sun may reduce the glare enough so the body’s natural reflex to turn away may be lessened. This can result in some people looking longer and damaging their retinas a condition known as solar retinopathy. Permanent damage or blindness can result.
“In this area, 43 percent of the sun’s diameter will be covered at greatest eclipse,” Keel said.
In Birmingham, the moment of greatest eclipse will occur at 11:19 a.m., according to Fred Espenak at NASA’s Goddard Space Flight Center. Statewide, the moment of greatest eclipse varies by only a few minutes, ranging from approximately 11:17 a.m. in Mobile to about 11:20 a.m. in Huntsville.
The eclipse will last about 3 hours, beginning in Tuscaloosa at roughly 9:45 a.m. and ending at about 12:50 p.m.
The amount of sunlight blocked by the moon will not be enough to cause a detectable darkening or an eerie cast, as was the case in the last total eclipse visible from the continental United States on Feb. 26, 1979.
“Even if half the sunlight were blocked, if you didn’t tell anyone they would never know there was something different with the sun’s light,” Keel said.
Following the Christmas Day eclipse, the next partial solar eclipse visible from the Southeast will be on Dec. 14, 2001, Keel said. The next total solar eclipse visible from the United States will be in August of 2017.
The Christmas Day viewing at UA is free and open to the public. Gallalee Hall is located on the UA campus near the intersection of Hackberry Lane and University Boulevard in Tuscaloosa.
For more information about the viewing, contact UA’s department of physics and astronomy at 205/348-5050.
Contact
Chris Bryant, Assistant Director of Media Relations, 205/348-8323
Source
Dr. William Keel, 205/348-1641