One-Two Solar Punch Could Ignite Auroras Aug. 2

The bright feature at left is a burst of electrons and protons (subatomic particles that make up atoms) shot off from the sun on the morning of July 29. It's expected to arrive and affect Earth's magnetic field sometime Tuesday afternoon. Credit: NASA/ESA
The bright feature at left is a burst of electrons and protons (subatomic particles that make up atoms) shot off from the sun on the morning of July 29. It’s expected to arrive and affect Earth’s magnetic field sometime Tuesday afternoon. The photo was taken by the Solar and Heliospheric Observatory (SOHO) which uses a circular mask to block the glare of direct sunlight. Credit: NASA/ESA

A blast of solar plasma coupled with a gust of particles from a coronal hole has left the gate and is now racing toward Earth. NOAA space weather forecasters in Boulder, Col. are predicting that the duo of duo of subatomic solar exhalations will reach our planet sometime tomorrow morning (Aug. 2) and initiate a G2 or moderate geomagnetic storm. The storm’s expected to peak through the afternoon (night in Europe) and continue as a G1 storm well into the night.

A wider view of the CME also photographed by SOHO but using a different coronagraph, the instrument used to block the sun. Credit: NASA/ESA
A wider view of the July 29th CME also photographed by SOHO but using a different coronagraph, the instrument used to block the sun. The tiny dots are stars. Credit: NASA/ESA

Timing’s great for aurora, assuming it occurs in the wake of the blast. The moon will be new and completely absent from the sky. Find a place with a good view toward the northern horizon and start watching in late twilight when the stars come out. The most common form the aurora takes is a low, rainbow-like arc spanning from northwest to northeast about a fist above the northern horizon. Rays usually poke out from the arc, but it’s so hard to know in advance exactly what to expect. Just be ready. If you have a digital camera (not a smartphone), you can attach it to a tripod to take pictures of any aurora that might show.


July 29, 2016 Graze of Aldebaran by Paul Maley

Last week, the waning crescent moon briefly covered up the bright star Aldebaran at dawn, an event called an occultation. Those of us who lived north of the “occulting zone” saw a wonderfully close conjunction instead. But for observers stationed along a narrow line, the moon grazed the star and provided a spectacular show. Lunar mountain peaks repeatedly covered and uncovered the star as the moon slowly tracked eastward in its orbit, producing a series of flashes as Aldebaran flickered back and forth into view.


July 29, 2016 Graze of Aldebaran by Steve Preston

Occultation enthusiast Brad Timerson shared these fine videos with me just a short time ago, and I enthusiastically pass them your way. The fluttering you see in both is due to the unsteadiness of the atmosphere at the moon’s low altitude. Be sure to watch them to the finish to see all the cool flashes. If you’d like to become involved in observing and timing occultations, I encourage you to visit the International Occultation Timing Association’s (IOTA) site.