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(meteorobs) CCD image of meteor trail

I have a CCD frame which has a meteor-like trail.  It was taken with
the Nordic Optical Telescope 2.56m on La Palma using a 2048*2048 CCD
last year.  The meteor was a nuisance at the time because it passed
unerringly through the centre of my target galaxy image, a dwarf(!) in
the Virgo cluster.

I believe that is it a meteor, rather than a satellite for a number of
reasons, although the evidence is far from conclusive.

1) The latitude was low and it was an hour before twilight began.  The
skies go from daylight to darkness very quickly at lower latitudes and
you see far fewer satellites than from the UK.

2) Also studying the image carefully shows that it was tumbling every
14 arcseconds---the trail has a corkscrew-like ripple.  Given a
typical angular speed of a satellite (well typical of the ones I see
when telescopic observing) of 15 arcmin/sec, that gives a tumble
frequency around 60Hz.  Yes the putative satellite could be out of
control or some space junk.

There aren't many arcsecond-resolution images of meteor trails to look
at.  Tumbling might be quite common; rippled meteor trains have been
seen.  Given the 14 large CCD mosaics in use or under development on
big telescopes, I expect that many more meteors will be captured.  If
the data are archived and well documented, we might be able to glean
information on faint meteors from such images.

3) There is a hint of some diffuse emission around the trail,
indicative of a train.  The field of view is only 6.2 arcmin, so
looking for a variation of the wavelength of the ripples across the
field isn't likely to help discriminate.

From the point of view of publicity material it might as well be a
meteor.


I won't post the GIF file because it's about 200k.  E-mail me if you
are seriously interested to see it soon; it will eventually appear on
the IMO Web pages...  I could produce a smaller cropped version if
there's a demand.  I'm reluctant to place it on anon-ftp, as I've been
saving the image to promote telescopic-meteor observing.  Some
magazines demand virgin images.  Does the Web count?

Malcolm
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