Very impressive Nick and well done for capturing from the visitor centre. The last time I was up there (pre-covid) the visitor centre still hadn't opened.

Andrew

-----Original Message-----
From: baa-comet@simplelists.com [mailto:baa-comet@simplelists.com] On Behalf Of Nick James
Sent: 19 September 2023 09:54
To: baa-comet@simplelists.com
Subject: [BAA Comets] C/2023 P1 (Nishimura) at perihelion +1d

Last night (Sept 18.83) I managed to get an image of this comet from 2100m altitude on La Palma when it was only 1 degree above the horizon.
The sky was very transparent and a stacked image shows stars to 8th magnitude at the same elevation as the comet. Using a star of magnitude
6.9 I estimate the total magnitude of the comet as 3.4. This is probably an underestimate given that much of the outer coma will be lost in the very bright background sky but I think it is not far off.

This is consistent with the magnitude prediction from pre-perihelion observations so I think this comet is performing as expected.

This is the cropped image:

https://britastro.org/observations/observation.php?id=20230918_231556_76d8b2a376760ba7

There was a very strong background gradient across the image which has been removed.

The following link shows the observing setup. A very clear western horizon with occasional cumulous blowing up the side of the mountain. My thanks to the Vistor's Centre for giving us access.

https://nickdjames.com/Comets/2023/2023p1/DSC00750.jpg

Nick James. BAA Comet Section.
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