What to watch for on April 8th as totality sweeps across the continent.
The time has come. Seven years ago on an August afternoon, the shadow on the Moon swept across the United States. Now we’re in the one month stretch, leading up to the big ticket astronomical event for 2024: the April 8th total solar eclipse spanning North America.
This is the last total solar eclipse for the ‘lower 48 states’ until August 23rd, 2044. Totality does nick remote northwest corner of the state of Alaska on March 30th, 2033. The path of totality on April 8th spans Mexico, the contiguous United States from Texas to Maine, and the Canadian Maritimes.
The eclipse will be partial from southeast Alaska, all the way down to the very northwest edge of South America. Hawaii will see a rising partial. On the other end, Iceland and the very western coast of Ireland will see the reverse underway at sunset.
A Penumbral Prelude
The first eclipse season of 2024 actually begins on the night of Sunday/Monday March 24/25. A penumbral lunar eclipse that night puts the whole celestial game into play. This subtle eclipse is visible from the Americas. Don’t expect to see much more than a slight ragged darkening on the southwest limb of the Moon around 7:12 Universal Time.
Though it’s a slight affair, this penumbral eclipse means that the nodes where the Moon’s path intersect the ecliptic are aligning for the total solar eclipse two weeks later. Though the 2017 event was an ascending node eclipse, the 2024 one is a descending node event, crisscrossing the path.
Tales of the Saros
This eclipse is member 30 of the 71 eclipses in solar saros series 139. This saros began way back on May 17th, 1501, and produced its first fully total solar eclipse (as opposed to a hybrid annular-total) on December 21st, 1843. It’ll cease doing so with the brief total solar eclipse of March 26th, 2601, and finally end on July 3rd, 2763.
One famous alumni for saros 139 occurred one exeligmos (three saroses or 54 years) ago on March 7th, 1970. This eclipse moved right up the U.S. East Coast in a path just slightly east of the upcoming eclipse. The three saros period is crucial, as each pass shifts the path 120 degrees in longitude westward, and three brings it nearly back around the globe full circle. The 1970 eclipse is one of two suspects referenced in Carly Simon’s song You’re so Vain… and the April 8th eclipse passes over the very tip of northern Nova Scotia. Will someone once again take their “Learjet to Nova Scotia, to see a total eclipse of the Sun?”
To be sure, we enjoy living in an epoch on a planet where total solar eclipses can occur… but this won’t always be the case. The Moon is slowly receding from the Earth, meaning that in about 600 million years time, all solar eclipses will be partial or annular only. Already, in the current 5,000 year epoch, annulars are now more common than totals. We’re also not the only place in the solar system where you could stand and see a moon versus the Sun in a close fit; the surfaces of the Jovian moons witness something similar about twice a decade.
Chasing the Shadow of the Moon
On Monday April 8th, the action begins when the penumbral (partial) shadow of the Moon first touches down over the South Pacific at 15:42 Universal Time (UT). Then, the inner umbral shadow touches down over the south-central Pacific at 16:42 UT, sweeping its way to the northeast. The shadow then first makes landfall over the Pacific coast of Mexico at 18:09 UT, and reaches its maximum duration of 4 minutes and 28 seconds over northern Mexico just shy of the Texas border.
This eclipse is on the long side of medium, with a maximum totality of just over three minutes shy of the maximum 7 minutes 32 seconds possible.
The 198 kilometer-wide shadow then continues to sweep 2,517 kilometers per hour to the northeast, intersecting the path of the 2017 eclipse over the states of Missouri, Illinois and Kentucky around 19:00 UT. Continuing its trek, the shadow then ranges over Lake Erie, northern New England and the Canadian Maritime provinces until departs the Earth over the North Atlantic at 19:55 UT. The final partial phases of the eclipse wrap up at 20:52 UT.
Millions live along the path of totality or within an easy day drive from the path. Major cities, including Dallas-Fort Worth, Indianapolis and Buffalo are all in the eclipse path. It’s well worth it to make the trip to the path to witness a total solar eclipse; even a deep 99% partial (such as an annular eclipse) is still pretty bright, something you might not notice otherwise.
“We urge anyone who can to go inside the path of total solar eclipse on April 8,” Michael Zeiler (Great American Eclipse) told Universe Today. “It will be an amazing experience when the sunlight suddenly disappears and the Sun’s stunning corona shimmers in the darkened sky. A total solar eclipse is nature’s most beautiful sight and you will never regret the effort to go see totality. If hotels are booked, stay with a friend or relative or go camping.”
“If someone in a location of 95% partial solar eclipse and says they will see most of the interesting phenomena, sorry but they’re wrong,” says Zeiler. “You have to be inside the path of totality with clear skies to see the full glory of totality. It’s the difference between watching the World Series final game in person or staying in a car in the stadium parking lot listening to the radio.”
Eclipse Safety
Proper safety precautions must be adhered to during all partial phases of the eclipse. This means covering finder-scopes, and either projecting the eclipsed Sun or using eclipse glasses meant for solar viewing. Approved glasses are stamped “Conforms to ISO 12312-2 standards for safe observation of the Sun” on the arms. Check those 2017 eclipse glasses in the daylight for cracks or pinholes before using them on eclipse day. NASA has a good page on eclipse safety, and tips on building a pinhole projector.
Wild Card Weather
We should know just what the weather might do about a week out from eclipse day. Likewise, we should start to have an idea of just how photogenic the partially eclipsed Sun will be in terms of sunspots, with a peek at what’s starting to rotate into view around April 1st. We’re nearing maximum for Solar Cycle 25, so we could be in for a fairly active Sun.
Best bets for clear skies are on Texas and Mexico, though April cloud cover can be fickle along the entire track. Keep in mind, you don’t need a crystal clear sky to see the eclipse; just a good view of the Sun. We had memorable views of the partially eclipsed Sun in 2017 leading up to totality, filtered though an approaching cloud bank.
Mobility and road access is key on eclipse day. Range and options dwindle hours prior as to where to head to to observe. NOAA’s GOES-East is a great site to see how the potential cloud cover situation is developing, come eclipse day. Don’t despair if clouds thwart the view: nearly every eclipse chaser has at least one story of the one that got away, and plans made to head to the next.
As the partial phases deepen, watch for crescent Suns dappling the ground. These are cast though natural pinhole projectors such as gaps in tree leaves and lattice-work. Spaghetti strainers or cheese graters are great tools for replicating this effect. Projecting the Sun back on a high contrast surface such as a piece of white paper can really enhance the view.
What to Expect During Totality
If it’s your first time experiencing totality, I’d advise you to simply enjoy the experience. The scant few minutes of totality goes by pretty quickly. Most people are surprised by the abrupt transition from broad daylight, to an eerie otherworldly twilight. You can drop the glasses as totality begins, and note the glow that circles the horizon. Jupiter and Venus will be visible near the eclipsed Sun. Also, watch for the +1st magnitude stars Aldebaran, Betelgeuse and -1st magnitude Sirius, all above the general horizon. Imagers may be treated views of Comet 12P Pons-Brooks, just two weeks from perihelion.
Fun fact: comets have been discovered during eclipses, as occurred on November 1st, 1948.
Totality is the only time you’ll see the corona, the ethereal outermost atmosphere of the Sun. The streamers of the corona can look different from one eclipse to the next. Seasoned eclipse chasers can actually tell which eclipse a given image is from, based on the appearance of the corona.
Temperatures may drop, and nocturnal wildlife may be briefly fooled by the onset of a false dusk. In 2017, we suddenly faced an onslaught of mosquitoes as totality fell over the Smoky Mountains of North Carolina.
As totality deepens, ask yourself: what would you think, centuries or millennia ago, if you were going about your daily business and such an event occurred, without warning?
These days, it is possible to nab a quick photo during totality with a smartphone camera. Be sure to shoot in RAW/Pro mode, and have your settings at the ready. Totality comes and goes very quickly. Here’s a great link to shooting an eclipse with your smartphone, and DSLR settings for totality. Check out this amazing smartphone eclipse video, courtesy of Tom Kerss:
— Tom Kerss FRAS (@tomkerss) March 6, 2024
The reappearance of the ’diamond ring’ effect as sunlight streams down the valleys along the lunar limb signals that its time to put the eclipse glasses back on. Folks along the edge of the path may witness a string of similar flashing effects known as Baily’s Beads. Key sites may also see the elusive ‘double diamond ring’ effect.
Chasing Eclipses Worldwide
Bitten by the ‘eclipse bug?’ The next total solar eclipse isn’t until August 12th, 2026 across Greenland, Iceland, and northern Spain. Incidentally, Spain becomes totality central after 2024. Two more eclipses grace the Iberian peninsula: a total on August 2nd, 2027 and an annular on January 26th, 2028.
Lots of amateur and professional projects are also underway leading up to the eclipse. We also typically see amazing views of the eclipse from space. These include views from ESA’s Proba-2 mission, NOAA’s GOES satellites, and from the International Space Station.
Also, expect NASA to livestream the event, come eclipse day.
And me? In an act of astronomical hubris, I’m once again tempting clouds and heading to northern Maine come eclipse day. This one has a special significance for us. It’s the only time that totality graces my hometown of Mapleton, Maine for this century. My rationale is, if we’re clouded out, we’ll then have an argument to chase after the next one…
Good luck, good eclipse chasing to all that live in or are headed to the path of totality, and clear skies!