Helen,

Thanks. It is pretty exciting for us old-timers too!

The comet is currently 2.77 au from Earth so 1 arcsec corresponds to
2,000km. The new coma has expanded to 34 arcsec diameter in a day which
implies an expansion velocity of 390 m/s. This is a lot faster than the
previous outbursts unless I've got my maths badly wrong...

Nick.

On 15/11/2023 17:41, Helen Usher - helen.usher at yahoo.co.uk (via
baa-comet list) wrote:
>   Yes QuickLOOK on LCO images giving rp measured with a 5" radius aperture using the PS1 magnitude system as 9.6 now against 14.6 on Monday.  Really looking forward to the excitement of our school children monitoring this again!