Is anyone getting short exposures of the nucleus/coma to see what features might be there, and to compare with visual observations of that area? I guess everyone is focusing on the tail at the moment.

Owen

Sent from Mail for Windows 10

From: Richard Miles - rmiles.btee at btinternet.com
Sent: 12 July 2020 12:38
To: baa-comet@simplelists.com
Subject: Re: [BAA Comets] 2020 F3 (NEOWISE) on2020 July 11.06

Further to Nick's reply - Yes, the striated features or striae are real and are well shown in Nick's, Damian Peach's and Michael Jaeger's recent images.

The structures are partly associated with cyclic variations in the amount of material (gas and dust) released by an irregularly-shaped nucleus as it spins and is subjected to periodic changes in the amount of solar energy the surface absorbs. You also get changes in spin rate and spin-axis direction when the nucleus is very active like this.

Richard

----- Original Message -----

From: seargent@ozemail.com.au

To: baa-comet@simplelists.com

Sent: Sunday, July 12, 2020 1:27 AM

Subject: Re: [BAA Comets] 2020 F3 (NEOWISE) on2020 July 11.06

Richard & all,

There seems to be "streaks" in the dust tail. Are these stria or simply effects of the processing?

David

----- Original Message -----

From:

baa-comet@simplelists.com

To:

<baa-comet@simplelists.com>

Cc:

Sent:

Sat, 11 Jul 2020 12:20:18 +0100

Subject:

Re: [BAA Comets] 2020 F3 (NEOWISE) on2020 July 11.06

Richard,

Great images. It was a stunning sight last night for those of us lucky
enough to have clear skies. I have loads of images of the comet and the
really spectacular NLCs from this morning but I have rushed to process a
couple taken with different focal lengths, 80mm and 200mm. In both cases
the photocentre is not saturated so there should be a load of detail I
can pull out later.

http://www.nickdjames.com/Comets/2020/2020f3_20200711_0120_ndj.jpg
http://www.nickdjames.com/Comets/2020/2020f3_20200711_0045_ndj.jpg

Hoping for clear skies again tonight. This must be the best comet seen
from the UK since Hale-Bopp in 1997.

Nick.

On 11/07/2020 12:08, Richard Miles - rmiles.btee at btinternet.com (via
baa-comet list) wrote:
> Here's my best effort from the early hours last night.
>
> I imaged both with a V filter and unfiltered. With the comet being so
> low in the sky, unfiltered images showed the effects of atmospheric
> dispersion smearing out the star images slightly plus more sky gradient,
> so although I have a stack of 24 x 30 sec unfiltered, the 15 x 30 sec
> stack is the better result.
>
> No background sky gradient filter has been applied as there are subtle
> contrast differences, which would otherwise be lost.
>
> Also have a few B, V, r and i images taken with the 0.35-m I've yet to
> look at.
>
> Richard
>
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