Exceptional Aurora Borealis display
By John Veterlein
(Story dated: October 30, 2003)

Fig. 1: The "corona" at Oct. 30, 00h 12m

The much heralded display of the Aurora Borealis (see "Sky Notes" website) came to fruition on the night October 29/30.

The skies from Rousay were cloudy with rain in the early evening, but it soon became evident that there was an exceptional auroral glow over the entire sky. Breaks in the clouds at around 20h 30m showed auroral activity in the form of rays, mostly in the east (fig. 2) and, unusually, south-east.

Fig 2: Looking east at Oct. 29, 21h 21m

With improving visibility (at times the entire sky was clear of cloud) it became evident that most (but not all) auroral features were present. One of the most impressive aspects of this display was the formation of bands and rays due south (fig. 3); even arcs - usually seen in the north and as far as the zenith - could be seen to engulf Mars low in the south-west.

Fig. 3 Looking south at Oct. 30 00h 02m

The other significant features was the strength and duration of the corona (fig. 1). This appeared somewhat south of the zenith and contained a deep purple colour at times. The radiating bands to the zenith encompassed the corona and spanned the entire great circle east to west.

The activity lasted throughout the dark hours into dawn of the morning of Thursday.

The two main sunspot groups have now passed the Sun's central meridian (fig. 4); the first large group has passed out of sight off the western limb.

Fig. 4 The Sun, Oct. 30 09h 40m