After processing of my images from Jan 18/19 and Jan 20/21 I should mention
some other interesting observations adding to the picture:
- images of C/2020 V2 on Jan 18.88 UT show an unexpected ion tail of length 0.7°
- images of C/2022 E3 on Jan 19.05 UT show the prominent ion tail extending
  beyond the border of the image at 2.6°
- images of C/2022 A2 on Jan 19.07 UT show an unexpected ion tail of length
  larger than 1.1° (extending beyond the border of image)
and
- images of C/2020 V2 on Jan 20.79 UT do only show a marginal trace of an ion
  tail (length ~5') despite having tripled the total exposure time

Unfortunately I was not able to observe C/2022 A2 and C/2022 E3 a second time
due to poor weather.

The three comets C/2022 E3, C/2022 A2 and C/2020 V2 do have quite different solar
distances (from 1.1 to 2.5 AU) but appear to be located within a spatial angle of
about 50 degrees seen from the sun. Could it be possible that the changes in
ion tail activity of those comets are triggered by the same solar event
propagating in the interplanetary magnetic field?

Thomas

> Am Sat, 21 Jan 2023 08:02:12 +0000
> schrieb Nick James <ndj@nickdjames.com>:
>
> Thanks for all of the observations of the Jan 19 disconnection event. I
> should be able to work out velocities and the time of the magnetic field
> boundary crossing with the data I have received. I can then compare this
> with the expected environment in the region of the comet.
>
> Before spacraft comet ion tails were the only way to measure the
> interplanetary magnetic field and the solar wind in situ.
>
> Since Jan 19 the ion tail has been much fainter and this morning it
> looked very different to the day before:
>
> https://britastro.org/observations/observation.php?id=20230121_063542_098aeb0bd999d079
>
> Nick.
>
>
> On 19/01/2023 13:49, Peter Tickner - peter.tickner1472 at btinternet.com
> (via baa-comet list) wrote:
> > I've also now put a normal animation n my Flickr page which is better
> > quality - link is: https://flic.kr/p/2ocmo58
> >
> >
> >
> > Peter T
> >
> >
> >
> > From: baa-comet@simplelists.com [mailto:baa-comet@simplelists.com]
> > Sent: 19 January 2023 12:59
> > To: baa-comet@simplelists.com
> > Cc: 'Nick James'
> > Subject: [BAA Comets] E3 tail separation
> >
> >
> >
> > I've managed to upload an animated gif to my BAA member's page with much
> > reduced file sizes (my original images are all full frame!) which shows that
> > the separation process was already under way when I started imaging at 01:50
> > UT.
> >
> >
> >
> > If anyone has any helpful ideas how I might better process and present the
> > data from my images I'd welcome the advice!
> >
> >
> >
> > Peter T
> >
> > To unsubscribe from this list please go to
> > https://www.simplelists.com
> >
> > To unsubscribe from this list please go to https://www.simplelists.com
> >
>
> To unsubscribe from this list please go to https://www.simplelists.com/confirm/?u=r3ocrmcO22g7WT8WdYPxQROJDgWbkEsh