If April 8’s total solar eclipse across North America did anything it put a pair of solar filters — in the form of eclipse glasses — in millions of households. It’s time to go find them because there’s something to see on the sun this week that could soon produce some impressive northern lights and southern lights.

The reason is an uptick in solar activity that’s leaving visible marks on the sun, with black sunspots seen on its southeast limb. If you have eclipse glasses you can go outside right now and see them. Counting sunspots — dark planet-sized regions of strong magnetic fields on the surface of the sun — are how scientists calculate how magnetically active the sun currently is. Sunspots are at a 23-year high.

Note: it is dangerous to look at the sun through anything other than a pair of certified safe solar filters (solar eclipse glasses) bearing the ISO 12312-2 international safety standard. Don’t make your own, don’t use sunglasses and don’t use welder’s glass (sometimes the latter if safe, but only if it’s Grade 13 or 14, which is hard to check). The American Astronomical Society keeps a list of Suppliers of Safe Solar Filters & Viewers.

The sun produced an X9 solar flare — a sudden and intense burst of radiation — on Oct. 3, the biggest of Solar Cycle 25 so far. Then, in the wake of the resulting aurora across the world on Oct. 10-11, the sun went quiet for a while. That ended dramatically when an X3.3 class solar flare was imaged by NASA’s SOHO spacecraft on Thursday, Oct. 24, quickly followed by a lesser M1.2 class solar flare and, on Friday, Oct. 25 by an M1.1 class solar flare. Saturday, Oct. 26 then saw M9.5 and X1.8 solar flares within an hour of each other. That’s very rare. A M1.6 flare followed soon after.

These recent solar flares are mostly coming from AR3873, AR3872 and AR3869, active regions very close together on the sun are part of a large group of sunspots on the sun’s southeast. Crucially, these active regions are on the Earth-facing side, so any coronal mass ejections — clouds of charged particles hurled from the sun — they produce could be Earth-directed. Since CMEs take a few days to reach Earth from the sun, that could be dramatic aurora displays in the coming week.

The sun only occupies half a degree of the sky, so trying to find it while wearing solar eclipse glasses is not easy. A good way to use solar eclipse glasses is to:

In the wake of Oct. 10-11’s aurora there was an announcement by NASA and the National Oceanic and Atmospheric Administration (NOAA)'s Solar Cycle 25 Prediction Panel that the sun had reached its “solar maximum” phase. This peak of the sun’s 11 year solar cycle, during which its magnetic activity waxes and wanes, could last for the next year or more.

That means a high chance of more Northern Lights. As a bonus, solar maximum will likely last longer than usual, think scientists, and likely produce frequent and powerful geomagnetic storms through 2026.

Solar eclipse glasses protect your eyes by blocking the short wavelength bluish visible light that can damage your retina. A consequence of us evolving under the sun, the solar spectrum peaks at the point where human eyes are most sensitive, with this short wavelength sunlight causing a photochemical reaction.

Solar eclipses glasses are made by passing boiling aluminum across polyester film to create aluminum-coated polyester filter. Other kinds of solar filters are made from dark polymer resin impregnated with carbon black.

Wishing you clear skies and wide eyes.