On Monday, Aug. 21, the moon's shadow will sweep across the country at more than 1,000 miles per hour, darkening skies from Oregon to South Carolina.
The first total solar eclipse visible from the continental United States since 1979, this is a big deal for dedicated sky watchers, with thousands, if not millions of people flocking to states in the path of the eclipse — Oregon is using the event as a chance to test the state's emergency infrastructure.
But just because you are not settled into a campsite in Oregon or the Great Smoky Mountains along the path of totality — that is, where the moon will totally block out the sun for 2½ minutes — does not mean there will be nothing to see. Here in Carroll County, we will experience a partial eclipse, about 80 percent of the sun will be covered by the moon.
Using proper viewing techniques can allow for safe viewing of this near-alignment of celestial bodies, and some libraries, nature centers and the Westminster Astronomical Society are holding eclipse parties for just this purpose.
Eclipse 101: What is it and why is everyone talking about it?
A total solar eclipse occurs when the moon passes between the Earth and the sun, casting a dark shadow on the earth's surface. As explained on NASA's eclipse website, this doesn't occur every time the moon orbits the Earth because the plane of the moon's orbit is slightly tilted with respect to Earth's orbit around the sun. An eclipse occurs only when the moon's orbit intersects Earth's around the sun; it usually misses the Earth, passing too high or too low to cast a shadow.
The last total solar eclipse visible from the continental United States was in 1979, but was visible only from the Pacific Northwest. The last time a total eclipse was visible across the entire country, that is, the moon's shadow swept from coast to coast, was in 1918. The next opportunity will be in the spring of 2024, when a total eclipse will sweep the Midwest from north to south.
Monday's eclipse is a member of Saros Series 145, a set of 77 solar eclipses occurring every 18 years and 11 days from the first on Jan. 4, 1639, to the last on April 17, 3009. Those at the very center of the moon's path Monday will experience a little more than 2½ minutes of totality, or night-like darkness as the moon blocks the sun. The longest eclipse in the series will give lucky skygazers a fully 7 minutes, 12 seconds of darkness — on June 25, 2522.
When exactly will the eclipse take place? Mathematician Stephen Wolfram has created an online calculator at www.precisioneclipse.com that can give the precise times based on a location. For Westminster, the moon will first begin passing in front of the sun at 1:17 p.m., and will reach maximum coverage at 2:41 p.m., the moon pass out of alignment with the sun by just after 4 p.m.
Wolfram has also written a history of the mathematics of predicting and calculating the timing of solar eclipses at blog.stephenwolfram.com.
What will you see?
What you see during the eclipse depends on where you stand in relation to the moon's shadow. Those within the path of totality will see the sky grow dark and the sun's wispy, super-heated corona appear from behind the black disc of the moon like the wispy, super-heated petals of a celestial sunflower. Stars may be visible, and the horizon in all directions will look like sunset while birds fall silent.
Those outside the path of totality will not experience darkness, but with the use of proper eye protection, or a pinhole projector, it will be possible to see the moon as it moves across the face the sun.
This is extremely important: Don't look at the sun. The only time during an eclipse that it is safe to look at the sun with naked eyes is during the brief period of totality. During the lead-up and after totality — and for people in Carroll County and other areas who will only see a partial eclipse — eclipse glasses, filtered optics or pinhole projectors must be used.
A pinhole project is simply a tiny hole in a piece of paper or cardboard. If held up to the sun during an eclipse, it will project an image of the crescent sun and shadow crescent moon, allowing you to view an image of the sun without looking at it directly.
NASA has video instructions on how to make a cereal box pinhole project on the agency's eclipse website at eclipsemega.movie/simulator. You needn't limit yourself to a single pinhole: Emily Lakdawalla, senior editor of the Planetary Society, has written a guide to making pinhole projects for children that make use of multiple pinholes in fun shapes, each one of which will project an image of the eclipse.
The Maryland Society of Eye Physicians and Surgeons has issued warnings for Marylanders who wish to view the eclipse, noting that using improper eye protection — sunglasses don't cut it — could seriously damage your retinas. Those who plan to take photos of the eclipse should likewise use filters for their cameras or smartphones.
Those who might have purchased eclipse glasses or filters on Amazon.com or elsewhere online should be aware of reports of fake or non-certified glasses that may not be safe for viewing the eclipse. The American Astronomical Society has created a list of verified safe manufacturers online at eclipse.aas.org/resources/solar-filters.
Where to see the eclipse (and get those eclipse glasses)?
Retailers like Lowe's and Walmart have been sold out of eclipse glasses for at least the past week. However, there are several organized eclipse viewing parties taking place in Carroll County on Monday, some of which will have a limited number of eclipse glasses available.
All of the Carroll County Public Library branches will be open to people coming by to view the eclipse, and there may be impromptu librarian talks on the topic, according to library Director of Community Engagement Dorothy Stoltz. There will also, however, be several formal events.
The Mount Airy and Finksburg library branches will be projecting the eclipse on large screens Monday afternoon, according to Lisa Picker, public relations manager for the library. She said the library branches had given out 2,000 free eclipse glasses in preparation of the event, and have only a small number remaining in reserve.
Bob Clark, Westminster Astronomical Society, will be on hand from 1 to 4 p.m. at Charlotte's Quest Nature Center in Manchester. There will be telescopes on hand with solar filters, including the on-site observatory's 15-inch Newtonian scope and a limited number of eclipse glasses available for a $1 donation.
"There is a nice, observable group of sunspots coming around the sun," Clark said. "They are entirely incidental to the main show — the eclipse — but it will be interesting to watch them get eclipsed."
Bear Branch Nature Center, in Westminster, will also have an eclipse party from 1 to 4 p.m., according to Park Operations Coordinator Dawn Harry. Bear Branch also has an observatory with a 14-inch telescope.
"We have our solar filters so we will have the observatory open," Harry said. "We are also going to attempt to, as long as the technology cooperates with us, live stream some videos from NASA from areas of the country where we actually have totality. If our planetarium cooperates we will have that going on in there and we will have a couple of crafts and fun stuff for the kids."
Bear Branch will also have a very limited number of eclipse glasses available for a $1 donation, Harry said, noting it will be a very laid-back event.
"Folks can come and go as they like," she said. "Come out and enjoy, we're out here on this hilltop."
If you go
Eclipse viewing parties for Monday, Aug. 21:
Bear Branch Nature Center: 1 to 4 p.m. at the nature center, 300 John Owings Road, Westminster. Enjoy views through solar filtered telescopes, eclipse crafts for kids and a limited number of eclipses glasses available for $1 donation. Event is free.
Charlotte’s Quest Nature Center: 1 to 4 p.m. at the nature center, 3400 Wilhelm Lane, Manchester. Enjoy views through solar filtered telescopes, eclipse crafts for kids and a limited number of eclipses glasses available for $1 donation. Event is free.
Eldersburg branch of the Carroll County Public Library: Noon to 3 p.m. at the library, 6400 W. Hemlock Dr., Eldersburg. Limited number of eclipse glasses available and program on the eclipse. Free.
Finksburg branch of CCPL: Noon to 3 p.m. at the library, 2265 Old Westminster Pike, Finksburg. View the eclipse projected on a large screen at the library. Free.
Mount Airy branch of CCPL: Noon to 3 p.m. at the library, 705 Ridge Ave., Mount Airy. View the eclipse projected on a large screen at the library. Free.