[BAA Comets] Tail structures in C/2011 L4 (PANSTARRS)

[Richard Miles]

Further to my earlier note at:
http://tech.groups.yahoo.com/group/comets-ml/message/21043

Here is a filtered image showing detail within the tail of the comet. 
Material appears to be preferentially streaming from the nucleus along two 
arcs when the FITS image is subjected to a 12-deg rotational gradient filter 
centred on the nucleus. (The same structures are also visible in the same 
image when filtered at other angles in the 5-12 degree range.) See:
http://www.britastro.org/~rmiles/Documents/C2011L4_20130314_RMiles_Vfilter_rot.jpg

Francois Kugel has also demonstrated a similar phenomenon in his image taken 
the same evening, although he used a 15-deg filter, which is tending to 
merge some of the detail. See:
http://www.astrosurf.com/obsdauban/pages/C2011L4.html

One interpretation of this appearance is that in reality the material 
towards the centre of the tail is reflecting/scattering less light than the 
outer portions whilst along the north-facing edge of the tail there is an 
excess of such material. Think of a somewhat hollow cone with a very 
asymmetric distribution of material around the periphery of the cone - seen 
from side-on.

Richard Miles
BAA