Stacking of five exposures, 120-sec each, obtained remotely from the Haleakala-Faulkes Telescope North on 2011, Aug. 5.5, through a 2.0-m f/10.0 Ritchey-Chretien + CCD + Bessel-R filter, under good seeing conditions, shows the presence of a secondary fragment embedded in the tail of comet 213P/Van Ness. This object, we named "parte-b", was placed about 5.3 arcmin in PA 239, with respect to the central condensation of the comet. It shows a tiny coma nearly 5-arcsec in diameter, with a tail of at least 22-arcsec in PA 235. Its m1 is R about 20, while its central condensation has R about 21.
A confirmatory observing session with the same set-up, has been obtained on 2011, Aug. 5.6: stacking of six exposures, 120-sec each shows again the fragment in the expected position, moving with the same proper motion of the comet.
Comet 213P shows also an obvious anti-tail, or dust-trail, at least 6-arcmin long in PA 58. Below our rendition of this feature, obtained during the same observing session:
by G. Sostero, H. Blyth, N. Howes and E. Guido