Denis,

It is difficult to see how the large coma could disappear overnight so I
expect this is something to do with your observation. What total
magnitude do you get using comphot? I have an image taken on the night
of Dec 31 from Chelmsford and I get 9.5 in a photomteric aperture of
diameter 6.3 arcmin. Recent estimates on COBS are brighter than this.

I had hoped to get some images from iTelescope T21 last night. I did,
but the telescope had a pointing error of over 10 degrees so no comet.
Not the kind of performance I would expect from a 200HR mount!

Nick.

On 01/01/2024 23:45, denis buczynski - buczynski8166 at btinternet.com
(via baa-comet list) wrote:
> Hello all,
> I imaged 12P tonight in excellent conditions using my 30cm f/4 Newtonian
> for 24x60s integrations.Very calm clear transparent sky. The magnitude
> of the central condensation remains around mag 13.. However the obvious
> coma that surrounded the central condensation seems to have disappeared.
> There is barely a trace of it on my stacked exposure. Unless I have made
> a hash of the processing.Strange, what do you make of it. Has anyone
> else imaged it tonight? Images attached.
> Denis
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