I know what feature you mean, I have been interested in it to for a
while, was surprised no one commented on it earlier!
Looks like traditional? type III tail?, like slanted gills on a fish,
or a half folded Asian style fan ;) please excuse my possibly poor
While those pics are all unbelievably amazing shots, and I love them.
I can't help but feel the observers and imagers located on the South
Island New Zealand (and Tasmania?) with far southerly views, captured
this feature the best, perhaps due to the greater elevation of P1 in
darker skies at the time/better views also, amongst other things of
course, where weather allowed, and when this nearest horizon feature
was out of twilight affected sky.
This page by Minoru Yoneto here
Has some great examples of it, with the feature clearly visible all the
way back to coma. As I cant link directly to images, only page, which
is in (un-translatable for me?) Japanese?. My favourites are the first
two from the evening of the 23rd jan. when large page is loaded, scroll
about a 6th of the way down, and the first one is in portrait mode and
a close-up-ish shot, second is below it, it is in landscape mode. sorry
thats the best I can do under circumstances :-)
On 01/03/2007, at 6:04 PM, jureatanus wrote:
> Hello Giovanni,
> > I think that you are referring to a synchronic band that has been
> emitted ~5 days before perihelion. A rendition from M. Fulle and S.
> Deiries is availbale here:
> > http://tinyurl.com/3cqjdv
> actually (I was not quite clear enough in my description) I am
> talking about the rather faint dust fan that is located sunward of
> the main (brightest) dust tail arc and behind (trailing) the coma.
> You can quite easily see it on Gordon Garradd's twilight image taken
> on Jan 20th:
> it goes almost perpendicularly to the brightest part of the dust
> tail, right behind the coma and is at very nearly right angle
> (clockwise direction) to the (presumably) neutral sodium tail.
> This dust fan can then be traced for quite a distance (sunward of the
> inner bright syndyne) and there are even hints of what appear to be
> synchronic bands in it. In fact these bands appear to make a faint
> criss cross pattern with striae at the bottom edge of the inner
> bright syndyne in this excellent image by Terry Lovejoy:
> This fan becomes more and more prominent as the main part of the dust
> tail fades during late January and first half of February, producing
> a wide V shape. For example, on Feb 9th:
> I'm no expert, but this dust feature is probably composed of large
> dust particles (judging by Mr. Fulle's diagrams). This is then
> evidence of presence of large dust particles in this comet's tail and
> possibly also evidence, that either only a small fraction of large
> particles disintegrates and forms striae or the parent particles of
> striae are in some middle size range? (there are probably papers
> being written on this right now, but it doesn't hurt to wonder about
> Clear skies!