RE: UPDATE: Comet 12P/Pons-Brooks: Time of outburst now more precise rmiles.btee@btinternet.com (05 Oct 2023 13:39 UTC)
Re: [BAA Comets] RE: UPDATE: Comet 12P/Pons-Brooks: Time of outburst now more precise Nick James (07 Oct 2023 20:16 UTC)
mismatch between the horns and the ion/dust tails Dr. Tony Phillips (09 Oct 2023 17:06 UTC)
RE: [BAA Comets] mismatch between the horns and the ion/dust tails rmiles.btee@btinternet.com (09 Oct 2023 17:40 UTC)
RE: [BAA Comets] mismatch between the horns and the ion/dust tails rmiles.btee@btinternet.com (09 Oct 2023 20:20 UTC)
Comet 12P/Pons-Brooks Peter Carson (06 Oct 2023 12:20 UTC)
Re: [BAA Comets] Comet 12P/Pons-Brooks Nick James (06 Oct 2023 20:11 UTC)

Re: [BAA Comets] RE: UPDATE: Comet 12P/Pons-Brooks: Time of outburst now more precise Nick James 07 Oct 2023 20:16 UTC
Richard,

I get an outer coma diameter expansion rate of 18 arcsec/day. At the
current distance (3.06 au) that corresponds to around 230 m/s expansion
velocity which is similar to last time (I got 200 m/s last time from
images measured over 7 days). The comet was 3.9 au out at the time of
the last major outburst.

Nick.

On 06/10/2023 00:53, rmiles.btee at btinternet.com (via baa-comet list)
wrote:
> Thanks Nick,
>
> Using the V band you are seeing more of the gas emission than what is
> visible this evening in the Sloan r' filter.
>
> B filter images may also be worthwhile.
>
> Alan Hale has caught the outburst in the later stages of its rise to
> maximum.
> He used a 'w' filter, which is almost like an unfiltered image.
> He just managed to avoid any significant saturation in 180-s exposures but
> it was a close-run thing!
>
> It'll be interesting to compare and contrast this event with the July 20
> one.
> Given the changing distance, it now looks like this was actually slightly
> less intense than the former one.
>
> Clear skies,
> Richard