This year on August 21st the lower continental United States will experience a solar eclipse, which is one of the most spectacular sights in all of nature. It is a great family activity with many options for safe viewing. Where you are on eclipse day will determine what you see, so let’s explore this topic and options for viewing in safe ways.
What exactly is a solar eclipse? Solar Eclipses take place at New Moon when the Sun, Moon, and Earth are in a perfect alignment and the Moon is casting a shadow here on planet Earth. They come in a variety of types – Total, Annular, and Partial depending on the alignment. There are two parts to the shadow, the darkest inner part is called the Umbra, and the lighter outer one is the Penumbra. Total solar eclipses take place when the angular size of the Sun and Moon are the same, meaning the Moon will “look like” it is the same size and it can appear to block out the Sun. While this happens the shadows trace a path over planet Earth. If you are inside the Umbral path you will see a total solar eclipse, if you are in the Penumbral portion you see a partial eclipse.
Eclipses follow the Saros Cycle which is a regular pattern, but the location is constantly changing so if you stay in one place they seem somewhat rare. There is a solar eclipse roughly every year and a half, but since the path is always changing it can be as long as 300 years between total solar eclipses occurring in the same location on the Earth. The last time there was a total solar eclipse in Maine was in in 1963 and the next time will be in 2024.
The eclipse on August 21st will be a total one, but to see it in totality you will need to be in the Umbral path which is only about 75 miles wide. The good news is the path crosses the entire country starting in western Oregon and finishing in eastern South Carolina. If you are outside the path, such as here in Maine, you will see a partial solar eclipse. Partial eclipses are not as spectacular as total ones, but they still offer a rare sight of the Moon covering the Sun.
Viewing solar eclipses are great activities for families as they are a very spectacular natural phenomena. The key is making sure to do so in a safe way so as not to do damage to one’s eyes. It is NEVER safe to look directly at the Sun, as its light is so bright it can burn the retina and do permanent eye damage. Our retinas do not have pain receptors, so that is why it is so important to take care when viewing solar eclipses. The Sun is no more powerful on a day of an eclipse than any other day, but people are curious and want to see what is happening, so they want to watch it over time. There are safe ways to do so.
One way is to do pinhole projection. In this method you are not looking at the Sun directly but rather projecting an image of it on the ground. All you need is a piece of paper with a pinhole poked in it. Stand with your back to the Sun and let the sunlight shine through it and project an image on the ground. This is 100% safe as you are looking at a projection and have your back to the Sun. It is one of the best ways to watch partial solar eclipses.
Another safe way is to use solar filter glasses. These specially designed glasses block out 99.9% of the Sun’s light allowing a safe amount through. Make sure you get glasses from a reputable source. Solar filter glasses should have an ISO 12312-2 stamp on them which means they are safe. Good sources are Rainbow Symphony, Inc. or American Paper Optics .
NASA and many public libraries (like Bangor Public Library) have a limited supply they will be giving out. I’ve also found good eclipse glasses at Lowes. All of these meet the safety requirements. When viewing through these glasses, the only thing you should be able to see is the Sun’s image – no clouds or halo. If you see anything besides the Sun, stop using them, as they are not safe! For more information on solar filter glasses safety see the American Astronomical Society page.
The best (and safest) way to insure safety is to view the event with a planetarium, science center, or astronomy club as they will have experienced people who know and understand the eye safety and often have special telescopes fitted with solar filters. If you are in the Greater Bangor Area, head up to Emera Astronomy Center who will hosting free viewing of the eclipse on August 21st from 1:00 to 4:00 pm. This event is in collaboration with the Bangor Public Library who will have a limited number of solar eclipse glasses to hand out onsite that day. The Penobscot Valley Star Gazers astronomy club will provide support with solar telescopes, and the astronomy center also will have 3 solar telescopes set up as well. The event is weather permitting.
What will we see here in Maine? Timings depend on your exact location, but in the Greater Bangor Area first contact (when the Moon starts to cover the Sun) will start at 1:36 pm EDT. The Moon will continue to cover more and more of the Sun until the maximum at 2:46 pm EDT when 54.7% of the Sun will be obscured. Then the Moon will move off, and last contact will be at 3:55 pm EDT. At maximum eclipse it will look like someone took a large “bite” out of the Sun! While it will not get dark here in Maine as there still is a great deal of the Sun showing, it still is an incredible event to witness. It will help you prepare for the next one in 2024 when Maine will be in the path of Totality. For information about times from your specific location or find out the path of totality see https://www.greatamericaneclipse.com/
To learn more about solar eclipses and the upcoming one on August 21st, join me for a free lecture at the Bangor Public Library on Wednesday, August 16 at 5:30 pm.
Or visit Emera Astronomy Center for its August monthly program Totality – Explore the Wonders of Eclipses on Fridays at 7:00 pm, or on August 21st at 10:00 am or 11:30 am.
Do get out and view this partial solar eclipse, making sure to do so safely! It is a wonderful event to experience with family and friends, so make sure not to miss it!