More Aurora Where Last Night’s Came From

Banks of fuzzy, green-glowing rays light up the northern sky last night around 10:45 p.m. Central time. Credit: Bob King

How sweet it is when an aurora forecast is dead-on. Last night, the northern lights performed as expected, actually better than expected, and they were right on schedule. At nightfall, I could see a glow low in the north, but because of a work project, didn’t go out for a real look until around 10:30-11 p.m. Every display is different. This one featured parallel banks of soft-edged rays that at least during my time never blew up into anything outrageous. They quietly pulsed and oozed about the bottom half of the northern sky.

Another view of a slow-moving but very active display last night (Sept. 27). Credit: Bob King

At the time, storm condition were moderate to strong. Although I hit the sack at around midnight, the aurora was still active and surged straight through the dawn. Based on the numbers (Kp=7) observers as far south as Illinois should have seen them. I always wonder what I miss when I finally give in and lay my head down on the pillow. Every so often, it’s a lot!

Checking back over last night, it appears the aurora hit its peak around 2-3 a.m. this morning Central time. This satellite forecast plot of the oval is from 2:45 a.m. Credit: NASA/NOAA

It’s my hope that at least some of you in the northern states caught part of the show. Tonight, activity is expected to decline to moderate and then minor storm levels a.k.a. a G1-G2 geomagnetic storm. As always I encourage you to look north at nightfall. The moon’s starting to get bright, but it’s still not so bad that the aurora can’t compete. If you’re unsure of what you’re seeing, you can always check it with a camera. Secure it to a tripod and make a 30-second exposure with the lens as wide open (maximum light) as it will go. That’s usually f/2.8, f/4 or f/4.5. Then press the review button and check the image on the back view screen. If it’s green, it’s aurora!

A color composite image of Earth taken on Sept. 22 by NASA’s OSIRIS-REx spacecraft just hours after the spacecraft completed its Earth Gravity Assist at a range of approximately 106,000 miles (170,000 km). Visible in this image are the Pacific Ocean and several familiar landmasses, including Australia in the lower left, and Baja California and the southwestern United States in the upper right. The dark vertical streaks at the top of the image are caused by short exposure times (less than three milliseconds). Credit: NASA’s Goddard Space Flight Center/University of Arizona

In other news, I thought you might like to see a photo of planet Earth taken by the OSIRIS-REx spacecraft during its close flyby on Sept. 22. Although the probe was shot into space at great speed on a mission to sample asteroid Bennu, it needed assistance from the Earth to change the angle of its orbit. Bennu’s orbit is tilted 6° to Earth’s, so NASA directed the craft to fly over the southern hemisphere just 11,000 miles above Antarctica.

The maneuver used the planet’s gravity to change the spacecraft’s direction and put it on the path toward Bennu. OSIRIS-REx is expected to arrive at the asteroid in late 2018.