The eclipsed Sun may be viewed in a variety of ways, and several of these don’t even require any sort of expensive equipment. In all cases, safety is of prime importance and, while observing is generally pretty simple, proper care should always be taken. Here are a few of the more common methods.
- During partial eclipse. Most of us grew up hearing the mantra, “never look at the Sun,” though we can modify this to “never look at the Sun without proper eye protection”. This is important to remember while viewing a solar eclipse. Even when the Sun is 99% eclipsed, its intensity is still more than enough to cause permanent eye damage.
- Solar Eclipse Glasses. These are inexpensive (usually only a dollar or two) and very easy to use. You can order them online from a variety of suppliers. Lowell Observatory will also have them available at the Lowell Eclipse Experience.
- Filtered telescopes, binoculars, or cameras. These use special filters that block out the harmful Sun rays. Several astronomers and educators will operate these instruments at the Lowell Eclipse Experience.
- Welders Goggles – Must have a rating of 14 or higher. These should not be used in conjunction with any magnifying instruments such as telescopes or binoculars, since those will intensify the sunlight and can cause the goggles to break from the intense heat.
- Pinhole Viewers. These allow observers to view a projected image of the Sun. A simple option involves two thin pieces of cardboard – one will be used to channel the sunlight, the other will act as a viewing screen. On one piece, poke a small hole (the size of a pin; thus the name!) through it. With your back to the Sun, hold it so the sunlight passes through and then position the other piece behind it, so that the Sun’s image falls onto it. This image will be a small, an inverted view of the Sun, and you can make the image larger or smaller by adjusting the distance between the two pieces of cardboard. Nature often creates such pinhole viewers for us, in the form of trees. As seen in the accompanying picture, captured at Lowell Observatory during a 2012 partial solar eclipse, clumping leaves or pine needles act in the same way as the pierced cardboard, leaving images of the Sun projected on a garage door.
- Projections from telescopes or binoculars. With the instrument mounted on a tripod and pointing at the Sun, sunlight will shine through the eyepiece onto a piece of paper, which serves as an observing screen.
- Remember to “never look at the Sun without proper eye protection”. Well, during totality, the Moon completely blocks the Sun from our view so you can then safely look in its direction without any eye protection. You will see the darkened outline of the Moon surrounded by the shimmering glow of the solar corona. While viewing can be done through telescopes, binoculars, or cameras (with their filters temporarily removed), the best way to observe totality is to simply gaze up and enjoy the experience, without trying to fiddle with those instruments. By the time totality ends (at the Lowell Eclipse Experience, an official will announce over a loudspeaker when totality begins and ends), you’ll need to revert back to observing the partial phase with the methods described above.
By Kevin Schindler, Lowell Observatory Public Information Officer and Historian