Hi all,

Well this is quite remarkable!  I started a search for the comet at 1730UT not expecting to see it as it wasn’t properly dark yet but there it was- quite unmistakable at a power of x38 in my 305mm Newtonian!   At low power visually it looks like a globular cluster.

I have made two visual estimates of its magnitude:

1736UT: Using the comparison star SAO47120 listed as Mv= 9.26 I made the estimate: 926-005 giving Mv= 9.31

1748UT: Using comparison star star SAO66550 which is listed as Mv= 9.50 I estimate 950+2 giving Mv= 9.30.

It should be noted that the second comparison star SAO66550 is of spectral class K2 so it’s B-V value is higher than SAO47120.  Nonetheless, I do feel that the second comparison star estimate is closer than the first so tonight I will list it as Mv= 9.30.

Nick:  I have two drawings which I will send on to you in due course.

Cheers,
-Paul

----
Dr. Paul G. Abel,
School of Physics & Astronomy,
University of Leicester,
University Road,
Leicester UK, LE1 7RH.

On 15 Nov 2023, at 17:59, Nick James <ndj@nickdjames.com> wrote:

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!

To unsubscribe from this list please go to https://archives.simplelists.com/confirm/?u=5UMcuamywWMYNcnq9t426PFOJ2QinK90