[BAA Comets] 2017 S3

[David Swan]

Good news - from the small stack of frames taken early morning of 18/07, it looks like the comet is still brightening.  Total integrated magnitude estimated by Comphot was 8.03 within 101.5 arcsec radius aperture. David



________________________________________
From: Comets-disc <comets-disc-bounces at lists.britastro.org> on behalf of Andrew Robertson <andrew at mail.fast-mail.net>
Sent: 16 July 2018 03:11:48
To: 'BAA Comets discussion list'
Subject: Re: [BAA Comets] 2017 S3

Forget to say: Observation made 16th July 2018 between 00:30 hrs UT and 01:00 hrs UT. From South Norfolk, skies about mag 5, Seeing Ant II to Ant III.

Andrew

-----Original Message-----
From: Andrew Robertson [mailto:andrew at fast-mail.net]
Sent: Monday, July 16, 2018 10:46 AM
To: 'BAA Comets discussion list' <comets-disc at lists.britastro.org>
Subject: RE: [BAA Comets] 2017 S3

Nick,

Getting that tail is impressive - I didn't see that visually last night. Ironically I was thinking of checking on it Saturday night to see if anything was happening but the skies were very claggy so I didn't bother, then Peter Carson's alert came in Sunday morning!

It's getting in a more awkward position for me so initially I looked for it in 15 x 70 binoculars and it was immediately obvious! I couldn't get my 12" scope on it so settled for my 8" OMC 200. What struck me was that it was noticeably brighter in the 8" scope than it had appeared on the 5th July in the 12" scope during its earlier outburst when I estimated it to be m 9.2 visually .

Tonight there were no suitable field stars in the 8" scope so I used my 15 x 70's to estimate it's magnitude:

HD 28734 at m6.7 was much brighter.
HD 29191 at mag 8 was a tad brighter.
HD 29091 at mag 8.3 was about spot on,

So I estimated it's visual magnitude in large binoculars to be mag 8.3.

Visually it had a stellar nucleus. The inner half of the coma was brighter than the outer half and it looked a bit grainy at times. The comet filter didn't help, just dimmed everything.

Great fun.

Andrew

-----Original Message-----
From: Comets-disc [mailto:comets-disc-bounces at lists.britastro.org] On Behalf Of Nick James
Sent: Monday, July 16, 2018 1:14 AM
To: BAA Comets discussion list <comets-disc at lists.britastro.org>
Subject: Re: [BAA Comets] 2017 S3

David,

Indeed. It is a really impressive comet tonight:

https://britastro.org/node/14803

The ion tail stretches out of my frame.

I get mag 8.49 in a 5.8 arcmin aperture using comphot and UCAC-4R.

Nick.

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