Eye Care Emporium

Safe Viewing of the April 8 Eclipse

11/06/2024 | Eye Care Emporium |

Eye Safety for Watching the Total Solar Eclipse

Get ready for the April 8, 2024, total solar eclipse! This spectacular total eclipse will sweep across North America on Monday afternoon, April 8, 2024. In a solar eclipse, the Moon passes in front of the Sun, casting its shadow onto the earth. Starting around noon CDT in Texas, the shadow will travel northeast and will exit Maine at about 4:30 pm EDT. If you are not on this centerline, you might not see the total eclipse, where the Sun is completely blocked.  But, most of the rest of the US will be able to see a partial eclipse. 

Read on below about some vision risks to your eyes, and how to safely watch the eclipse. While the eclipse is a unique astronomic event and will be viewed by many millions of people, some risks to your eyesight must be considered. So, below we point out some important safety guidelines to follow when viewing a total solar eclipse.  

                      IT IS NOT SAFE TO LOOK DIRECTLY AT THE SUN

  • Only view the Sun through special very dark eclipse glasses or a handheld solar viewer during the partial eclipse phases before and after totality.
  • You can view the eclipse directly without proper eye protection only when the Moon completely obscures the Sun’s bright face – during the brief and spectacular period known as totality. (You’ll know it’s safe when you can no longer see any part of the Sun through eclipse glasses or a solar viewer.)
  • As soon as you see even a little bit of the bright Sun reappear after totality, immediately put your eclipse glasses back on or use a handheld solar viewer to look at the Sun. (resource: https://science.nasa.gov/eclipses/safety/ ).

Below is a composite image that shows the progression of a total solar eclipse. The Sun is depicted in orange here, but it is very bright. You must not look directly at the Sun unless you have special eclipse glasses. 

A blue eye with a black background

This composite image of eleven pictures shows the progression of a total solar eclipse. Credit, NASA/Aubrey Gemignani. Fhttps://science.nasa.gov/eclipses/safety/           

                        Eye Safety for Partial and Full Solar Eclipses

Partial solar eclipses are different from total solar eclipses – there is no period of totality when the Moon completely blocks the Sun’s bright face. Most of the US will only see a partial eclipse on April 8, so during this partial solar eclipse, it is never safe to look directly at the eclipse without proper eye protection.

When watching a partial solar eclipse directly with your eyes, you must look through safe solar viewing glasses (“eclipse glassesâ€) or a safe handheld solar viewer at all times. Eclipse glasses are NOT regular sunglasses; regular sunglasses, no matter how dark, are not safe for viewing the Sun. Safe solar viewers (see the site https://eclipse.aas.org/eye-safety/viewers) are thousands of times darker and comply with international standards. 

  • Always inspect your eclipse glasses or handheld viewer before use; if torn, scratched, or otherwise damaged, discard the device. Always supervise children using solar viewers.
  • Do NOT look at the Sun through a camera lens, telescope, binoculars, or any other optical device while wearing eclipse glasses or using a handheld solar viewer — the concentrated solar rays will burn through the filter and cause serious eye injury.

       THERE IS A SIMPLE WAY TO SAFELY VIEW THE SOLAR ECLIPSE

If you don’t have eclipse glasses or a handheld solar viewer, you can use an indirect method, such as a pinhole projector, to view the eclipse while not looking directly at the Sun. 

A pinhole projector is like a camera lens, except the lens is tiny hole made in a piece of aluminum foil with a pin. This small opening projects an image of the Sun onto a nearby surface. With the Sun at your back, you can then safely view the projected image. Do NOT look at the Sun through the pinhole!

You can make your own personal eclipse projector in several easy ways. Using a cardboard box, a white sheet of paper, tape, scissors, and aluminum foil, you can make a portable viewer as in the picture below. With the Sun behind you, sunlight will stream through the pinhole punched into aluminum foil taped over a hole in one side of the box. During the partial phases of a solar eclipse, this will project a crescent Sun onto a sheet of paper taped to the inside of the box. Look into the box through another hole cut into the box to see the projected image.

A blue eye with a black background

See details at https://science.nasa.gov/eclipses/safety/

Another even easier way to make a pinhole projector with a piece of cardboard is from CalTech’s JPL website  https://www.jpl.nasa.gov/edu/learn/project/how-to-make-a-pinhole-camera/.