Practical advice about what to look for when the Moon covers the Sun on August 21.
The big day is finally here and you’re in the path of totality. After what seems like an interminable wait, the Moon takes a nibble out of the solar disc—first contact. Now what? Bear in mind that you’ll spend 98 percent of the eclipse watching the partial phases, so keep your eclipse viewer handy and ensure that there are solar filters on your optics.
If you don’t have eclipse glasses yet, note that we have bound a safe eclipse viewer into newsstand copies of the September/October issue of SkyNews. (Subscribers received their viewers with the of the July/August issue.) If you’re unsure if the eclipse glasses you already have are safe, check the list of approved eclipse viewers compiled by the American Astronomical Society. When in doubt, err on the side of caution.
The partial eclipse lasts from first contact to second contact, at which point totality begins. When is it safe to remove the solar filters? My advice is to take off the filters when people start yelling, “Baily’s beads,” but do not peer through any telescope, binoculars or camera yet—wait until the final brilliant ray of sunlight (the “diamond ring”) is gone. I’d further recommend you not look at Baily’s beads without an eclipse viewer covering your eyes—in part for safety but also because the beads will dazzle your eyes and compromise your ability to see the delicate solar corona during totality.
You can watch the second-contact diamond ring with your bare eyes (not through any optics), though I’d advise patience. People tend to call out the appearance of the diamond ring too soon. If you can restrain yourself, count slowly to three after you hear the first “diamond ring,” then put down your eclipse viewer and look up. You’ll be stunned by what you see.
As the diamond ring fades at second contact and totality begins, the red arc of the chromosphere emerges. Depending on the level of solar activity at the time, towering prominences might add to the scene. Observe these features quickly with binoculars or a telescope (no filters required!), as they’ll be rapidly covered by the encroaching lunar disc. Then explore the pale white solar corona stretching away on either side of the blacked-out Sun. In a scope at low magnification, you can trace loops, swirls and arcs that reveal magnetic field lines in the Sun’s atmosphere.
If you can tear your attention away from the eclipse, take in the entire sky. Venus has become a brilliant pinpoint, while the sky overall has diminished into a deep twilight. Scan the horizon, where you’ll see “sunset” everywhere. This 360-degree, yellow orange glow is sunlight shining, albeit feebly, outside of totality—just beyond the Moon’s dark umbral shadow in which you’re standing.
It’s Over Already?
All too soon, the corona brightens, in an area roughly opposite where the diamond ring vanished. Prominences (if any) rise from behind the Moon’s black disc, followed by the red arc of the chromosphere. A dazzling beacon of light erupts from the eclipsed Sun—the third-contact diamond ring. Enjoy it (without optics), but turn your gaze away as the corona fades and the diamond ring expands rapidly into a blinding crescent. Totality is over, and it’s time to put solar filters back on your instruments and to use your eclipse viewer once again.
Veteran eclipse chasers like to say that totality, no matter how long, seems to last eight seconds. If this is your first eclipse, you’ll likely feel the same way. As the partial phases unfold in reverse (filters on if you’re still watching!), you’ll probably be left with two burning questions: When and where is the next total eclipse of the Sun? (Hint: Turn to page 18 of the September/October issue of SkyNews.)
For more SkyNews eclipse coverage, visit here.
Paul Deans is a SkyNews contributor and has seen 10 total solar eclipses since 1972.