[AZ-Observing] Re: [amastro] Re: Aurora in Tucson

In reference to my earlier posting of observing the aurora down here in
Palominas, AZ (latitude 31.4N), I am now absolutely certain of a different
observation made about 10 minutes before seeing the main aurora display
which wasn't particularly strong or of long duration.  I'm not sure what the
magnetic effect would be called, but I've heard some terms such as 'eddies'
and magnetic field ringing.

At about 0830 UT, while out in the backyard observatory under a very dark
sky (say a LM of 6), I noticed over a span of about 1 minute several
extremely faint, barely perceptible widely spaced (10's of degrees) reddish
bands (spanning maybe 10 degrees wide) running from the north to the south,
almost from horizon to horizon. They each lasted maybe only a few seconds,
and I would say they were even fainter than the Gegenschein. At first I
passed them off, thinking they were some visual afterglow effect from using
my dim red light on a star chart.  But about 10 minutes later is when I
first noticed the developing aurora to the NE.  I observed the aurora for
about 15 minutes until it pretty much dissipated.  Going back to my
observing, I started thinking about these earlier faint bands again and did
several 'tests' to see if in fact my red light had led me to see them in
some way as visual persistance (using a red light for many years, this
effect never occurred before unless the red light was really bright).  I
repeated using the red light at my usual setting, and a few times at
somewhat brighter levels to see if these reddish bands would reoccur when
looking up to the sky after turning the light off.  They did not.  So I am
certain I was seeing some magnetic field effect that encompassed certain
paths of magnetic lines of flux and flowed from north to south.
Has anyone on the list ever encountered this effect before the onset of the
(rather) easily visible aurora?

Doug
----- Original Message ----- 
From: "Brian Skiff" <brian.skiff@xxxxxxxxxx>
To: <az-observing@xxxxxxxxxxxxx>
Cc: <amastro@xxxxxxxxxxxxxxx>; <mpml@xxxxxxxxxxxxxxx>
Sent: Wednesday, October 29, 2003 2:21 AM
Subject: [amastro] Re: [AZ-Observing] Aurora in Tucson


>      If you're sitting at the computer right now (9:20 UT), you can
> watch the aurorae from Flagstaff in living black-&-white on our
> webcam:
>
> http://www.lowell.edu/users/buie/wxpix
>
> Click in the lower image to see the last two hours of action.
>
> \Brian
>
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>
>
>

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