Hi Owen !
I have a short window of time when I can get the 25.4 cm Schmidt-Cassegrain on to the comet head. Unfortunately, it's so low that it is very near a street light, just above the neighbour's rooftop, and the aperture of the 'scope is obscured by the observatory wall to some extent. However, at 96x magnification, I can see quite a bit of detail in the head. The bright nucleus, which is almost stellar, extends into two lobes which then form the outermost starts of the sides of the tail. Just behind these lobes is a reasonably "dark" patch which is then filled completely further away from the head. The easternmost side of the tail is brighter and sharper and there is some coma just ahead of the bright nucleus. I cannot see striae, my eyes aren't good enough. I cannot detect any change in the head these last two days.
It would be interesting to compare with some digital shots of the head region.
Might be cloudy here for the next few days.
Mike
On 13 July 2020 at 09:09 "Owen Brazell - o.brazell at btinternet.com " <baa-comet@simplelists.com> wrote:
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
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 -----
To:
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
>
> To unsubscribe from this list please go to
> http://archives.simplelists.com
To unsubscribe from this list please go to http://archives.simplelists.comTo unsubscribe from this list please go to http://archives.simplelists.com
To unsubscribe from this list please go to http://archives.simplelists.com
To unsubscribe from this list please go to http://www.simplelists.com/confirm.php?u=8Z9y3XPLtw7WXvRQcmcR4DAMfKgWUhXJ