Beautiful image, Peter! Exceptional image quality for such small elongation ...

> Am Sun, 20 Aug 2023 10:41:16 +0100
> schrieb Peter Carson <petercarson100@gmail.com>:
>
> Hi All,
>
> Here’s my image taken this morning (20th) in twilight conditions.
>
> http://www.astromania.co.uk/2023P1_20230820_0357_PCarson.jpg
>
> The comet was just below the roofline of the adjacent observatory at my remote site in Extremadura, Spain, but fortunately, that roof was open until daylight.
>
>  
>
> My image records an ion tail around 26 arcminutes in length. The comet is mag 9.15 and has a 4.1 arcminute dia coma as measured in Comphot.
>
>  
>
> Hopefully, I’ll be able to access the low easterly sky tomorrow morning.
>
>  
>
> Peter
>
>  
>
> Peter Carson Z10
>
> Essex UK
>
>  
>
>  
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>  
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>  
>
> Sent from Mail for Windows
>
>  
>
> From: Nick James
> Sent: 19 August 2023 19:26
> To: baa-comet@simplelists.com
> Subject: Re: [BAA Comets] Comet C/2023 P1 (Nishimura)
>
>  
>
> I managed to image this comet on Thursday morning in a very bright and
>
> hazy sky:
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>  
>
> https://britastro.org/observations/observation.php?id=20230817_205409_67bcd83df81cc3cc
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>  
>
> I've used astrometry up to August 18 with the constraint e=1 to get the
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> following orbit for C/2023 P1 (Nishimura) using Findorb:
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>  
>
>     Perihelion 2023 Sep 17.624618 +/- 0.0249 TT;  Constraint: e=1
>
> Epoch 2023 Aug 17.0 TT = JDT 2460173.5   Earth MOID: 0.0779   Ve: 0.0426
>
> q   0.22560874 +/- 0.000322         (J2000 ecliptic)
>
>                                      Peri.  116.10237 +/- 0.08
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>                                      Node    66.93040 +/- 0.050
>
> e   1.0 +/- 0                       Incl.  132.40851 +/- 0.12
>
> From 56 observations 2023 Aug. 14-19; mean residual 1".30
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>  
>
> The attached plot shows the elongation of the comet using that orbit.
>
> The comet has been at an elongation of < 40 deg since the beginning of
>
> May and Nishimura discovered it as it reached around 34 deg rising out
>
> of the morning twilight. For amateur comet discovers searching the
>
> morning twilight sky is a key tactic. The orbit of this comet was almost
>
> perfectly designed to avoid the surveys.
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>  
>
> As it approaches perihelion in September the elongation will drop
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> rapidly and when the comet is at its brightest in September it will only
>
> be 12 degrees or so from the Sun. To see it then you will probably want
>
> to be high up a mountain but we'll see how things develop.
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>  
>
> The surveys could have picked it up back in April when the elongation
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> was much larger but it was then over 3au from the Sun and so would have
>
> been much fainter. I would expect that, once we have a better orbit,
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> we'll find it somewhere in the survey data.
>
>  
>
> Nick.
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>  
>
>  
>
> On 15/08/2023 22:16, Nick James wrote:
>
> > CBET 5285 announces the discovery of an 11th magnitude, diffuse comet by
>
> > the Japanese observer Hideo Nishimura on Aug 12.78 UT. The comet is
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> > currently at a small solar elongation (34 deg) but may be visible in the
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> > morning twilight. A number of visual observers have reported
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> > observations in the last day. The solar elongation is almost constant
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> > through to the end of August then decreases through September as the
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> > comet brightens.
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> >
>
> > The comet is currently in Gemini. At the start of nautical twilight at
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> > 52N tomorrow (Aug 16, 0330 UT) the comet will be around 14 degrees
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> > elevation.
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> >
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> > An ephemeris is available on JPL Horizons. Please send any observations
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> > to the section.
>
> >
>
> > Nick.
>
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