On a stack of 18 CCD images 60 seconds each in fairly good seeing a fuzziness was barely appreciated, I didn't report it to the central bureau for astronomical telegrams (CBAT) because to me, it wasn't clear enough if it was a comet.
However, other observatories noticed the diffuse aspect and the object has been recognized as a new non periodic comet.
Below you can see the analysis of the full with at half maximum for the stars in the image, most of them have FWHM = 2.5" which is good seeing for La Cañada, the comet, in red, has a much wider spread function.
Read a doc on how to detect low activity comets looking at the statistics of the FWHM.
References : MPEC 2009-F34, IAUC 9029 (subscribers only)