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For years, small groups of astronomy enthusiasts have traveled the world to chase rare solar eclipses. They have embarked on mid-ocean cruises, made eclipse-trail flights, and even traveled to Antarctica. In August 2017, millions across the United States witnessed a total solar eclipse visible from Oregon to South Carolina, with a partial eclipse visible for the rest of the continental United States.
Interest in the astronomical events sparked by this eclipse is likely to return with two visible eclipses occurring in the United States over the next year – an annular solar eclipse on October 14, 2023, and a total eclipse on April 8, 2024. But astrotourism – travel to national parks, observatories or other Natural dark-sky locations for viewing astronomical events — it’s not just about eclipse chasing.
According to a recent study, 80% of Americans and a third of the planet’s population are no longer able to see the Milky Way from their homes due to light pollution. As a result, most people have to travel to see meteor showers and other common astronomical events.
I am a space scientist with a passion for teaching physics, astronomy, and night sky photography. Every summer, I spend several nights in California’s Sierra Nevada Mountains, where the sky is dark enough to allow the Milky Way to be seen with the naked eye. My son and I also like to take road trips — often along US 395, the Eastern Sierra Scenic Byway — that coincide with eclipses and meteor showers.
There are two types of eclipses. A lunar eclipse occurs when the full moon passes through the Earth’s shadow. A solar eclipse occurs when the new moon briefly blocks the sun.
There are three types of solar eclipses. During a total eclipse, the Moon completely covers the Sun, or the time during which the Sun is a total eclipse, lasting for up to seven minutes. During a total eclipse, those in the eclipse’s path will see the sun’s corona, or outer atmosphere, behind the moon’s silhouette.
The Moon’s orbit around Earth is an ellipse, so the Moon can appear 15% smaller when it is farthest from Earth, its apogee, compared to its size when it is closest to Earth, or perigee. An annular eclipse occurs when the Moon does not completely cover the Sun’s disk, leaving a ring of sunlight around the Moon.
Finally, a partial eclipse occurs when the Moon blocks only part of the Sun’s disk, as the name suggests.
Meteor showers are a much more common astronomical event than eclipses, and can be seen from anywhere in the dark sky on Earth. Meteor showers occur when Earth’s orbit around the sun passes through dust left behind by a comet. The ground sweeps up the dust like a car speeding through a cloud of insects on the highway.
Meteor showers are named after the constellations from which meteors appear to emanate, although you don’t have to stare in that direction to see meteors. The most notable meteor shower, which occurs on roughly the same dates each year, is the Perseids, named after the constellation Perseus, peaking on the night of August 12-13; Gemini, named after the constellation Orion, on December 14-15; The Lyrids, named after the constellation Lyra, are on April 21-22. The night sky will be mostly moonless for the first two years of this year, but a nearly full moon will make it difficult to see 2024’s lyre shower.
One of the most important factors to consider when planning a stargazing outing or meteor shower viewing is the phase of the moon. The full moon rises at around 6pm and sets at 6am, making stargazing impossible due to its brightness. For ideal stargazing conditions, the moon should be below the horizon, and the best viewing conditions are during the new moon. You can use a moonrise and sunset calculator to determine the moon phase and sunrise and set times for any location on Earth.
Another important factor is the weather. Amateur astronomers always joke that the sky is cloudy during the most interesting astronomical events. For example, most major cities in the United States that lie in the path of the April 2024 eclipse had cloudy skies on April 8 60% of the time since 2000.
Most Americans live in areas with high light pollution. A light pollution map like lightpollutionmap.info can help pinpoint the nearest dark-sky location, which, in my case, is hours away. These maps often use the Bortle dark-sky scale, which ranges from 1 for very dark skies to 9 for very light-polluted city centers.
Although you may still see the brightest meteors from the outskirts of the city, the darker the sky, the more meteors you will see. In general, expect to see fewer than 25 meteors per hour. To see the complex structure of the Milky Way with the naked eye, look for a location with a Borthel index of 3 or less.
It is important to arrive at your chosen location early, preferably during daylight hours. Stumbling around in the dark in an unfamiliar location is a recipe for disaster and may also upset others already at the location. Arriving early also gives your eyes time to adapt to the darkness as night falls, as it usually takes 30 minutes or even more for your eyes to reach their full dark-adapting potential.
Be sure to carry a headlamp or flashlight that has a red light setting, as red light does not spoil night vision. Avoid using your phone, as even a quick glance at the screen can disrupt your eyes’ adaptation to the dark. If you use an app to view the sky, switch the app to night mode.
Plan ahead if you’re thinking of traveling to see one of the eclipses visible in the United States next year. If you’re in the path of the eclipse, stay put! If you’re traveling, staying in the same location overnight before and after the eclipse can help avoid the hours-long traffic jams that eclipse watchers will experience in 2017.
You should also not look at the sun directly with the naked eye, even during a total eclipse. You’ll need a pair of inexpensive eclipse glasses to view and enjoy the eclipse in full, but get yours early, as many stores are sold out during the 2017 eclipse.
No matter where you travel next year, don’t forget to look up at night and marvel at the beauty of the night sky far from the city lights.
Vahi Beroumian is a professor of physics and astronomy at the University of Southern California’s Dornsife College of Letters, Arts, and Sciences.
