4 easy eclipse activities for North and South America

On October 14, 2023, a solar eclipse will occur on Earth.

When, during a new Moon phase, the Sun, Moon, and Earth all line up in a row, a solar eclipse is possible. Whether the eclipse is a total eclipse (top) or an annular eclipse (bottom) is wholly dependent on the relative angular sizes of the Sun and Moon to an observer on Earth.

With the Moon near apogee, however, the Sun appears larger.

Right now, the largest (perigee) full Moon appears bigger than the Sun at all times of the year. However, over time, the Moon will migrate away, causing its angular diameter to shrink. When the perigee full Moon is smaller than the aphelion Sun, no total solar eclipses can occur anymore. The Moon varies by a much greater amount in angular size than the Sun owing to its more eccentric orbit around the Earth compared to Earth’s around the Sun.

The result is an annular eclipse for locations along the center-line.

Along the center-line of an annular eclipse, during the moment of mid-eclipse, the “ring of fire” feature will create a perfectly circular annulus of the portion of the Sun that cannot be eclipsed by the Moon. This photo was taken during the May 2012 annular eclipse, and while only about 50% of all solar eclipses are annular on Earth today, in another 600-650 million years, they all will be, as the Moon continues to spiral away from the Earth due to tidal braking.

However, nearly all North and South Americans will experience a partial eclipse.

This shows the path of the October 14, 2023 annular solar eclipse across North and South America. Observers within the red band will be in the path of annularity and will be able to observe a “ring of fire,” while those outside of it in the other shaded regions will only observe a partial solar eclipse. Almost all North and South Americans will get at least a partial eclipse.

Here are four fun, easy, and educational activities for enjoying during a partial eclipse.

This image, from Mir during the 1999 solar eclipse, shows a dark shadow of the Moon appearing on Earth. Right along the center-line of the eclipse, either a total solar eclipse or an annular solar eclipse will be seen, while everyone still within any portion of the Moon’s extended shadow will experience a partial eclipse.

1.) View the Sun directly.

Either eclipse glasses, solar filters, or welder’s shades (that are at least shade 14 or darker) are all tools that humans can leverage to view the Sun directly during a partial or annular solar eclipse, or even during no eclipse at all. During totality, however, you must remove them, or you won’t see anything at all.

You can do this any time with eclipse glasses, even with no eclipse.

The eclipse glasses that many of us obtain can be used at any time, even not during an eclipse, to view the disk of the Sun directly.

For superior views, put a solar filter on the outer lens of binoculars or a telescope.

A woman looks at the Sun through binoculars that have been fitted with solar filters over the outside lenses. During totality, it is safe to view the Sun’s corona with unfiltered telescopes or binoculars, but only if you ensure that you are not still viewing the Sun the instant totality ends or thereafter, as it can cause permanent eye damage and even blindness.

2.) Create a projection of the Sun.

This shows an example of a pinhole camera: where a tiny hole is poked into an otherwise opaque surface to allow just a “point” of sunlight to shine through. As the sunlight lands on the far end of the box shown here, it creates an image, or projection, of the Sun. This is especially useful during a partial eclipse.

The easiest, lowest-tech way is to build a pinhole camera.

Although there are many ways to construct a pinhole camera, so long as you have an opaque surface with a small hole in it to let sunlight through, and then a surface/screen to project that “pinhole” of light onto without letting too much stray light in, you should be able to see an (inverted) image of the Sun on the screen.

Projecting through binoculars/telescopes can create superior, large, magnified projections.

If you want to view a magnified projection of the Sun, either during a solar eclipse or at any other time, one simple solution is to mount binoculars onto a tripod and open only one eyepiece, letting the light through. The projected image of the Sun will be large enough to view any visible sunspots as well.

3.) Observe partially eclipsed shadows.

During a partial (or annular) solar eclipse, the normal shadows you’d see through the leaves of a tree instead make a crescent (or ring) like shape, as the spaces in between the tree leaves act like tiny pinhole cameras, projecting the image of the eclipsed Sun onto the surfaces beneath them.

Where sunlight “pokes” through shadows, eclipsed images appear.

During a partial solar eclipse, any circular hole that sunlight shines through won’t produce a circular image, but rather a projection of the partially eclipsed Sun: showing the Moon’s disk partially in front of it.

Colanders, kitchen skimmers, tree leaves, and criss-crossed fingers create fascinating sights.

The lowest-tech way to observe a projection of the Sun during a partial solar eclipse is to cross your fingers together, over your head, with your back facing toward the Sun. You’ll then see, in the spaces between your fingers, small images of the partially eclipsed Sun, rather than the more typical sight of a full Sun.

4.) Measure the outside temperature.

By recording the temperature before the eclipse starts, then periodically through maximum eclipse and afterward until the final phase of the eclipse ends, you can monitor the severity and timing of any temperature drops in your location.

As the Moon blocks the Sun’s light, it also blocks the Sun’s heat.

During an eclipse, the solar radiation reaching Earth’s surface plummets owing to the presence of the Moon’s umbral and penumbral shadows. Here, the path of the August 21, 2017 eclipse is shown. As the Sun becomes blocked, temperatures can plummet significantly.

Temperatures can drop by up to 28 °F (16 °C) during a total eclipse; by less during partial eclipses.

By recording the temperature in regular (e.g., 5 minute) intervals during a solar eclipse, a temperature change can be observed. The coldest temperatures don’t typically occur during maximum eclipse, but slightly afterward.

Find your exact eclipse times by location here.

This partial solar eclipse, captured over Arlington, VA in 2021, shows the Moon’s disk partially blotting out the Sun. The Moon’s motion across the Sun’s disk corresponds to a portion of the Moon’s 360 degree revolution around the Earth, and extrapolating what we observe during an eclipse to a full lunar month enables us to estimate the duration of a lunar month.

For those experiencing totality next year, October provides a great “practice run” for these activities.

The path of totality of the April 8, 2024 total solar eclipse cuts from southwest Mexico up through Texas, Oklahoma, Arkansas, Missouri, Illinois, Indiana, Ohio, Pennsylvania, New York, Vermont, New Hampshire, Maine, and Canada. Everyone along the center-line of the eclipse in 2024 also experienced at least a partial eclipse on October 14, 2023, and a penumbral lunar eclipse on March 25, 2024.

Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words.