This image, taken 10 days later shows the comet essentially unchanged.
The diffuse and unconcentrated nature of the coma is shown on the screen
print from Astrometrica (below)
The 'Object Verification' form in Astrometrica allows the user to check
that the program has correctly centred on the brightest part of the image.
An aperture radius of 3 pixels was used here, the red circle representing
a diameter of 9 arc seconds.
The graph at top right shows a solid red curve representing the
theoretical fit of the measured brightness values of the pixels in the
image. The profile of the coma does not follow this line and flattens off
without any concentration in the central 3 pixels (about 5 arcseconds).
Measuring accurate astrometry is difficult in these circumstances.