[BAA Comets] C/2017 S3 PanSTARRS

[Andrew Robertson]

Personally I find it hard enough making an accurate visual magnitude estimate by de-focusing stars in the field to the same size when you can see the comet. But if you can't even see it.....

You don't know if it's fainter than the faintest star you can see, at the very best you would be saying it's fainter than.....

I suppose that may be of some value.

Regards,
Andrew

-----Original Message-----
From: Comets-disc [mailto:comets-disc-bounces at lists.britastro.org] On Behalf Of Nick James
Sent: Friday, July 27, 2018 7:05 AM
To: BAA Comets discussion list <comets-disc at lists.britastro.org>
Subject: Re: [BAA Comets] C/2017 S3 PanSTARRS

Mike,

I guess that seems like a reasonable approach but visual observers might want to comment. 

Nick.



On 26/07/2018 10:43, mike.collins12 at tiscali.co.uk wrote:
> Hi Nick !
> 
> Unable to see 2017 S3 in 4" refractor then switched to 10" S-C as 
> comet had moved sufficiently but by then it was too light. That was on 
> July 25 00:36-01:47 UT.
> So I spent a lot of time on this one observation.
> 
> Not sure how to report a negative observation unless one assumes that 
> the comet is the same coma diameter as previously seen and do a 
> magnitude estimate of the faintest star defocussed to the same degree and unable to be detected.
> 
> 21P observations continue but the bright Moon and hazy sky causing problems.
> 
> Cheers
> 
> Mike
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