All part of the service, Nick.

That's great news that you imaged it on July 29 - that's perfect and fits
with my estimate of the timing.
I didn't expect anyone to be following 17P given that it's at about 60
degrees solar elongation in the morning sky!

I used the images of its 2015 January strong outburst to estimate the number
of days the outburst coma has been expanding - that earlier event is well
documented on the BAA website at:
https://britastro.org/node/6226

Cheers,
Richard

----- Original Message -----
From: "Nick James" <ndj@nickdjames.com>
To: <baa-comet@simplelists.com>
Sent: Monday, August 09, 2021 9:43 PM
Subject: Re: [BAA Comets] Comet 17P/Holmes has gone into outburst !!

> Richard,
>
> Thanks for the alert.
>
> The formatting seems to be messed up on your comets-ml message but I think
> it says that the comet was 17.30 on July 20 and 16.02 on August 8. How did
> you determine the time of the outburst as Aug 3?
>
> My last image of it was on July 29 when it was around mag 17.0 (unfiltered
> vs Gaia DR2 G) in a 9 arcsec radius aperture:
>
> https://britastro.org/cometobs/17p/17p_20210729_020259_ndj.html
>
> Morning objects are not good for me on weekdays but I'll have a go at it
> next time I get a chance.
>
> Nick.
>
>
> On 09/08/2021 22:05, Richard Miles - rmiles.btee at btinternet.com (via
> baa-comet list) wrote:
>> 17P/Holmes is well known for its unique 13-14 magnitude mega-outburst of
>> 2007 October 24.
>> This enormous outburst did not disrupt its nucleus, which appears to be
>> still intact.
>>
>> On or about 2021 August 03, the comet was just 3 degrees away from
>> reaching the same position in its orbit when it underwent its dramatic
>> mega-outburst of 2007. During the intervening years, it has made not
>> quite two orbits of the Sun.
>>
>> The current outburst looks to be 1.4 magnitudes amplitude, meaning that
>> it has brightened by almost a factor of 4, i.e. a very significant event
>> indeed.
>>
>> We might expect some repeat small outbursts every 36-44 days.
>>
>> More details have been posted on the 'comets-ml' mailing list at:
>>
>> https://groups.io/g/comets-ml/message/29901
>>
>> Richard Miles
>>
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