Updated

Updated · Livescience.com · Aug 27

96% Lunar Eclipse May Coincide With G2 Red Auroras Across Parts of the U.S. Tonight

Updated

Updated · Livescience.com · Aug 27

96% Lunar Eclipse May Coincide With G2 Red Auroras Across Parts of the U.S. Tonight

Q: With the Kp index lagging by hours, how can you track the exact moment tonight's geomagnetic storm peaks during the eclipse?

Don’t rely on the Kp index tonight if you want the exact peak. Kp is a backward-looking, three-hour global average and can lag the real storm by hours, so it often misses short auroral surges during an eclipse window. The better way is to watch NOAA’s real-time solar-wind data from the L1 monitor now feeding the SWPC solar-wind page, with ACE as backup. The key signal is the interplanetary magnetic field’s Bz component. If Bz turns strongly southward and stays there — roughly below about -10 nanoteslas for a sustained stretch — while total field strength Bt is elevated and solar-wind speed and density rise, that is the clearest sign the storm is intensifying at Earth. A sudden density jump can also mark the CME shock arrival. To follow the actual peak over your sky, pair that data with NOAA’s OVATION aurora nowcast and local magnetometer traces or live aurora webcams. Those tools respond far faster than Kp and can show when the auroral oval expands or a substorm suddenly erupts. In practice, the “peak” for viewers may come in short bursts rather than one neat Kp maximum. For tonight, NOAA’s forecast puts the strongest activity near 9:03 p.m. EDT, just before the eclipse begins at 9:23 p.m. EDT, but CME timing can shift by several hours. So the best strategy is to monitor live Bz, Bt, speed and density continuously through the eclipse rather than waiting for a Kp update.

Q: Will your smartphone camera reveal hidden auroral colors during tonight's darkened lunar eclipse that your naked eye can't see?

Yes. A smartphone camera can often reveal auroral colors and structure that your eyes may miss tonight, especially if the display is faint. That is because phone cameras in Night Mode or other long-exposure settings gather light for several seconds, while human vision in darkness is much less sensitive to color. Faint auroras that look like a gray or whitish cloud to the naked eye can show up as green, red, pink or violet on a phone screen. Aurora guides and forecasters routinely use smartphones to confirm whether a dim glow is actually aurora. Tonight’s partial lunar eclipse may improve those odds. With about 96% of the Moon entering Earth’s shadow, the sky will be darker than during a normal full moon, reducing glare and making weak aurora easier to detect. If NOAA’s forecast G1 to G2 geomagnetic storm materializes, some observers could even record both the copper-red eclipsed Moon and red or green aurora in the same sky, particularly farther north. A phone is not guaranteed to show dramatic colors everywhere. Results will depend on your latitude, cloud cover, local light pollution and how strong the storm becomes in real time. In many mid-latitude places, the aurora may still sit low on the northern horizon and look faint. For the best chance, use the main camera lens, turn on Night Mode or a 3- to 10-second exposure, keep the phone steady on a tripod or solid surface, and point it toward the northern horizon. That is often the quickest way to detect hidden auroral color.

3 articles · Updated · Livescience.com · Aug 27

A partial lunar eclipse starting at 9:23 p.m. EDT is set to turn 96% of the moon coppery red, with peak darkness arriving just after midnight.
NOAA has also issued a G2 geomagnetic storm warning beginning at 9:03 p.m. EDT after an M-class solar flare and coronal mass ejection from sunspot 4513.
That overlap could make auroras visible from New York to Idaho, while Canada and Alaska offer the best chance of seeing both the eclipse and northern lights together.
Stronger storm conditions can produce rarer red auroras above 120 miles, and the dimmed eclipsed moon may improve visibility by reducing the usual full-moon glare.
The event is expected to be the deepest lunar eclipse visible anywhere until the next total lunar eclipse on Dec. 31, 2028.