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I was hoping some of the experienced people on this list could help me
understand whether something I saw was a light pillar or what.
I grew up around 30 degrees latitude so I've never seen an aurora. On
Oct 29, when the CME from the Oct 28 solar event had hit earth (it had
hit about 14 hours earlier), I hoped to see something so I travelled to
a dark area north of San Francisco to see if I could spot anything. I
had picked an area that had little light pollution.
I was on the south side of Lake Sonoma (a large reservoir). The Milky
Way was clear and bright and I was able to easily walk around from the
light of the sky (no moon). My location was 38.7N, 123W at about 800'
elevation. (I was on a hill above the lake, not at the shore).
A high pressure area ("cold front" by California standards) moved in
that day. The temperature was about 50 degrees Fahrenheit (10 C) (per
the thermometer on my car while I drove and while parked). The wind was
quite brisk, enough to push me around a bit. I'd estimate the wind to
be 20-30 miles per hour. The entire time, there were no clouds
anywhere to be seen.
I was at the location from about 11:30PM to 2AM (standard time). When
I didn't see any signs of aurora, I took advantage of the dark skies and
was just touring the skies with a small telescope.
Approximately 12:35AM, I looked up from the telescope and saw, without
my glasses (-4 diopters), what appeared to be a spotlight shining up,
directly below the North Star. I fumbled around to put on my glasses
and saw the same thing. The telescope was completely inappropriate for
this, so I went to dig out some binoculars. Unfortunately by the time I
got the binoculars out, the light had disappeared. I could find no
trace of it.
At the time, I thought I was seeing some sort of light that was
associated with an aurora, so I was thinking its source was above it and
didn't associate it with the ground.
I took note at the time that the light appeared to go up more or less
from the ground to about 60% of the way to the North Star (ie, 22
degrees). The light appeared white, but was not brilliantly white. As
I said, my initial reaction was that it looked like a spotlight. (But
of course there were no spotlights in use that night.) I didn't try to
measure the width of the column of light but it was neither broad (as in
an aurora) nor pencil-like.
The air was exceptionally clear so I would discount its being, say, a
police car's light that was shone straight up as there was little in the
air to show its path. It also would have been at least 2 miles distant
(to the other side of the lake). The light didn't move while I saw
it. Unfortunately, I saw neither its start nor its end.
When I got home, I tried to find a description of what I had seen. I
quickly found references to pillars. Although I had thought of this
beam as being below the North Star, it turned out it was also above the
lights of a town 10 miles (16km) north. I was directly south of
Cloverdale, a city with a population of about 5,000. Its lights were
obvious but their glow went up less than 5 degrees. About 10 degrees to
the west were the lights of a city of 16,000 that was 30 miles away. A
star was visible just barely above the horizon in between the two.
One description I read indicated that pillars often went to 20 degrees
above the horizon which corresponded to what I had seen. I felt sure
that this is what I had seen.
My question about it being a pillar is that the air temperature (50F/10C
at 800') seemed well above what I've seen for most other descriptions of
pillars. Also, I wonder about the fact that the wind was brisk. I
don't know if that would allow for an alignment of ice crystals that
would allow for this to be seen for about 30 seconds to a minute. I'm
sure at higher altitudes the air was colder but also the wind would
likely be stronger. (The location is maybe 50 miles inland from the
Pacific Ocean with the wind blowing from the NW.)
If the pillar's light source was the town and the ice crystals were
directly above it, the top of the pillar would be 4 miles in altitude.
I expect though that the ice crystals would be half way between the
light source and me, so the top would be 2 miles up. I also am pretty
sure that the pillar went most of the way to the ground so that I'd
expect that if this were a pillar, I would have seen reflections off ice
crystals that were no more than a half mile (1km) in altitude. While I
could believe it was freezing at a half-mile in altitude, I'm not sure
that there would be the necessary conditions to get these ice crystals.
Another possibility is that the light source for this pillar was much
further north and that I was seeing something that was a reflection of
that light. Then the ice crystals would be much higher in the
atmosphere at a much colder temperature. There are no significant
cities north of my location for about 350 miles. (But, for all I know,
it could be reflecting an aurora that I couldn't see.)
I was hoping that those more familiar with pillars and auroras could
clarify what it was that I saw.
Thanks!
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