Friday, March 3, 2017
ISOLATED ARC AURORA Taken by Alan Dyer on March 2, 2017 @ near Gleichen, Alberta
Heres a panorama from west (left) to southeast (right) of an aurora display, March 2, 2017, from southern Alberta, with a classic aurora oval to the north, and the odd-looking isolated arc to the west and east (and it passed overhead) glowng pink in color, with a bare hint of green fringe. These arcs are not uncommon but seem to be unique to latitudes far to the south of the main auroral oval. In this case, the arc was overhead for us at 51° North, while the main oval was 5° to 10° farther north. They are often red, showing only fringes of green at times. They are often mistakenly called proton arcs.
Jupiter is rising to the right of the eastern arc. Orion is setting at far left.
This is a stitch of 8 segments, each with the 20mm Sigma lens at f/2 for 20 seconds each at ISO 3200, rather long but I wanted to bring out the faint isolated arc.