To the editor,
As a retired optometrist, an amateur astronomer, and someone who traveled to Kelly-Hopkinsville, Kentucky, on August 21, 2017, to view the total solar eclipse, I have some helpful information for those who want to watch and photograph the April 8 event.
Most importantly, I would be remiss if I did not warn you against looking directly at the sun, or pointing any optical device at the sun, without special glasses designed to look at the sun. (Look for glasses marked “ISO 12312-2”). Do not trust homemade filters!
Perhaps as a child you used a magnifying glass to burn a hole in a leaf. If so, you know that focusing the sun’s rays concentrates the heat. If you look at the sun, you are concentrating the sun’s rays on your retina. There is no pain, but it will burn a hole in your retina, causing a blind spot in your vision. There is no treatment, and it will last forever.
Any optical device you use, such as a telescope, camera, or binoculars, must also have a special solar filter.
While at the Kentucky viewing site, I noticed that almost everyone had trouble aiming their telescopes and cameras at the sun. It seems so simple, but in actual practice it is very difficult to point something at the sun without accidentally looking at the sun. People were using their hats, visors, newspapers, umbrellas, etc., to block the sun while they aligned their optical instruments. You can solve this problem if you build your own “visor” for your device. Just take a piece of cardboard, or Styrofoam, about one foot square, cut a hole in it to fit around the rim on the lens and then cover that hole with a solar filter (if your device does not already have its own filter). Buy a few extra solar sunglasses and use those lenses to cover your camera, binoculars, etc.
For example, for a smart phone camera, use a one-foot square piece of cardboard, cut a hole about the size of the lens, cover that hole with a solar filter from your solar glasses, stick your phone camera to the cardboard with double sided tape (or Velcro). Now the cardboard will shield your eyes while you are looking for the sun on your screen.
Be prepared and comfortable with your equipment. Practice photographing the sun now. Don’t wait until the day of the eclipse.
Dr. J. Eric “Rick” Vandemark
North Baltimore
