[BAA Comets] [comets-ml] 17P/ Holmes - possible outburst

[Richard Miles]

Not a problem Chris.

At least it serves as an alert to observers to keep a close watch for a 
possible outburst of 17P over the next month or two. There is a significant 
chance of an outburst during this time interval when the comet nucleus will 
experience increasingly cooler maximum daytime temperatures whilst it 
recedes from perihelion.

Alan Hale has already commented that 17P may have had at least a small 
outburst when he was observing it back in early June. Outbursts of less than 
1 mag were clearly detected back in 2009 and in 2012, and so it is likely 
that the nucleus is prone to undergo small outbursts, most of which may have 
been missed in the past. Observers should therefore keep a close watch for 
the signs of any outbursts such as condensed coma, or a significant 
brightening of the nuclear magnitude.

Good luck,
Richard Miles
BAA

P.S. In reporting photometry, in the interest of standardisation /precision, 
can observers please report the nuclear magnitude using a photometric 
aperture having a diameter as close to 11 arcseconds as possible, and also 
use R magnitudes from the UCAC4 catalogue as reference? That catalogue 
incorporates the AAVSO APASS photometry, which makes it significantly more 
accurate than most other astrometric/photometric catalogues.


----- Original Message ----- 
From: "Bomber2 Panther outbackmanyep at hotmail.com [comets-ml]" 
<comets-ml at yahoogroups.com>
To: "Comets-ML" <comets-ml at yahoogroups.com>
Sent: Wednesday, July 30, 2014 6:26 PM
Subject: [Bulk] [comets-ml] 17P/ Holmes - possible outburst


>
> Hi Richard,
>
> It is a false alarm, I checked the new position just now and I can't see 
> anything, I checked Guide 9.0 and the star is not charted. I did notice 
> that I have an APASS listing of 11.9 for that star not marked.
>
>
> I re-traced last nights position just now visually, and the star is there.
>
> Sorry for mucking everyone around!
>
>
> Cheers,
> Chris W