Sun Won’t Quit — Aurora May Return Tonight Thru Wednesday

Aldebaran stands a short distance from the bright lunar limb about a minute before being occulted this morning at 7:28 a.m. CDT in broad daylight seen from Duluth, Minn. The photo was made with a telescope and an ordinary mobile phone. Credit: Bob King

I almost didn’t wake up in time for this morning’s occultation of Aldebaran by the last quarter moon. Let’s just say I made myself get up. Sure glad I did. Despite some fire haze, Aldebaran waited just off the moon’s edge through the telescope. The contrast of that bit of fire with the broad, daylight-tinted moon was very cool to see. At 7:28 a.m., the star went zip and disappeared behind the moon’s bright limb.

That zip was not instantaneous but seemed to take ever so slightly longer, which I took as a sign of Aldebaran’s orange giant status and its relative nearness to Earth. Although still appearing as a point through a telescope, the star is 44 times the size of the sun and 65 light years away. Combined, that means it has a enough heft to take just a fraction of a second longer to be covered by the moon than a smaller star.

If you missed this Aldebaran occultation, the next will occur on November 5-6 for the eastern U.S. and Europe.

The X8 flare from sunspot group 2673 created this angry looking coronal mass ejection (CME) off the sun’s western limb on September 10th. Although the material was too far off the Earth-sun line to cause northern lights, the explosion did temporarily increase radiation exposure in Earth’s upper atmosphere, exposing airplane passengers at 40,000 feet to twice the normal dose of  radiation received at that altitude. Credit: NASA/ESA

The X8-class flare from the sunspot group 2673 continues to make news. It blasted a big CME into space though not aimed at Earth directly. However, the eruption was powerful enough to send solar protons (hydrogen atoms basically but stripped of their electrons) whizzing this way. En route, they zapped the digital camera of NASA’s Solar and Heliospheric Observatory (SOHO), streaking across the sensor and creating a blizzard of electronic noise. On Earth arrival, they sparked a radiation storm in the atmosphere with some protons even reaching the ground.

Whole lotta noise! These are tracks recorded by a storm of protons leaving the sun in the wake of Sunday’s X8 flare by SOHO’s coronagraph camera. SOHO is located at the a relatively stable orbital location called the L1 Lagrange point about 932,000 miles from Earth toward the sun. Click here to see a time lapse of the proton storm hitting. Credit: NASA/ESA

These were recorded by monitoring stations in Antarctica, the Arctic and other high latitudes. Although it’s unusual for material from the sun to make reach the surface of the Earth, it’s happened 73 times since measurements began in 1942, according to

With all this excitement, you’d expect the blast to find a way to couple to Earth’s magnetic field and fire up the aurora, but it was too far off the line for that to happen. Instead, a coronal hole and shocks from multiple streams of particles from the sun will juice up minor and moderate geomagnetic storms beginning a little before dawn (Central time) tomorrow morning, September 13 and through tomorrow night. The moon now rises late, so these are good opportunities for watching for northern and southern lights.

2 Responses

  1. Jolene

    Will there be a chance to see northern lights early this coming week in the Tofte MN area Sunday Sept 17th thru Wed? I hoped to see them in Alaska when I was there a couple of weeks ago. No such luck.

Comments are closed.