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------ Original Message ------
From: jjgsgp@...
To: [email protected]
Sent: Sunday, December 29th 2024, 01:44
Subject: Re: [comets-ml] Unusual brightening of comet C/2023 Q1


Thomas, Denis, Peter, Jakub, all,Some recent further visual data :C/2023 Q1 (PANSTARRS):2024 Dec. 28.82 UT: m1=11.7 (AQ), Dia.=6', DC=1/, 20 cm SCT (77x).[ Faint, large and very diffuse outer coma, slightly enhanced through Swan Band filter. Nearby field stars checked in DSS. At 133x : m=13.3 (AQ) for the 1' inner coma diameter. Limiting star magnitude near comet : 14.5 (AQ). Mountain location, very clear sky.].( Collada de Aralla, 1500 m, Leon, Spain )And other comments ?:Denis, in your posts ?in this thread you mention the word "debate". For my part, by contributing my data I do not want to discuss the photometric measurements obtained with CCD/CMOS, I only add complementary information from another perspective ...On the other hand, the mentioned visual estimates of C/2023 Q1 and 29P cannot be compared, even if they are now of similar magnitude m1 and apparent diameter : the comae structure and composition are different, and Q1 is more diffuse.Thomas, I fully agree with you : "The aperture diameter MUST be taken into account when comparing data. The second important parameter is the spectral range covered."But regarding your report ( 2024-12-23.46 UT, m1=14.1, coma diam. 5'), I obviously disagree when you say "I would be very much surprised if it would be possible to detect the same amount of coma size visually".Best regards,J. J. Gonzalez Suarez---------------------------------------------------------------------------------


On Sun, Dec 29, 2024 at 12:07?AM Observatory Gr?mme via groups.io <observatorygromme@...> wrote:
Dear All,

For the moment i measure magnitude 16 using SDSS r' filter. Uncalibrated images. PhotAp 6.1arcsec


From: [email protected] <[email protected]> on behalf of David Moore(Ireland) via groups.io <davefriend0@...> Sent: Saturday, December 28, 2024 2:19 PM To: [email protected] <[email protected]> Subject: Re: [comets-ml] Unusual brightening of comet C/2023 Q1 ?


Skyglow?

If coma diameter is 4' that's 45,000 sq "
I think I saw a figure of 21mag per sq arcsec?
So airglow alone would 'add' 11.6mag i.e. a patch of dark sky 4' in diameter is mag9.4?

Is my maths wrong!?



On Saturday 28 December 2024 at 12:05:34 GMT, Thomas Lehmann via groups.io <t.lehmann@...> wrote:


Hi Denis, here is a heavily processed image. Pretty ugly though, but it might serve for illustration purposes. Something I'd add to my "total" coma mesurement within 5': the brighness measurement (statistical) uncertainty is about 0.15mag. Best wishes Thomas > Am Sat, 28 Dec 2024 11:43:28 +0000 (GMT) > schrieb "Denis Buczynski via groups.io" <buczynski8166@...>: > > Hi Thomas, > I appreciate all you say in this regard. > I would be more convinced that there was an extensive coma present if I > could see an image showing this coma. Whether it be from fast f/2 > telescopes in excellent dark skies or from anywhere else . It only > requires someone posting a current image showing an extensive coma to > put this "debate " to rest.We have yet to see one. > Best wishes > Denis Buczynski > > >? ? ? ? ------ Original Message ------ >? ? ? ? From: t.lehmann@... >? ? ? ? To: jjgsgp@...

Cc: [email protected] >? ? ? ? Sent: Saturday, December 28th 2024,

11:17 >? ? ? ? Subject: Re: [comets-ml] Unusual brightening of comet C/2023 Q1 > > > >? Dear all, > >? thanks for the numerous observation reports, especially to Denis's and > Peter's >? measurements over longer time span. > >? I'd like to emphasize that any brightness measurement MUST be read in >? conjunction to the measurement aperture used. The aperture diameter > MUST be >? taken into account when comparing data. The second important parameter > is >? the spectral range covered. The brightening from gaseous outbursts can > be

? more prominent in the green filtered images than in unfiltered (or >

red) images. > >? About visual estimates. >? My report of 2024-12-23.46 UT, m1=14.1, coma diam. 5' >? is derived from images using a fast f/2.2 scope under excellent skies > having >? a limited stellar magnitude of 21mag and using heavy smoothing and > contrast >? enhancement. I would be very much surprised if it would be possible to > detect >? the same amount of coma size visually. It is even harder for me to > accept that

? I have missed 90% of the comets coma flux in my measurement - which would be >? the case if the magnitude were near ~11.6mag - though I

cannot rule > out some >? additional outburst has happened recently. >

? Anyway, I'd like to encourage anyone to continue monitoring the

comet. >? For those doing imaging, it would be nice if you could measure the > coma >? additionally using a true aperture diameter of d=15000km and 30000km > at the >? comet (and report filter information) so we would be able to construct > a >? combined light curve of the inner coma brightness. > >? Thanks >? Thomas > > >? > Am Sat, 28 Dec 2024 07:54:29 +0100 >? > schrieb "jjgonzalez jjgonzalez via groups.io"? > <jjgsgp@...>: >? > >? > Thomas, Denis, Alan, all, >? >

? > Obviously, I am also interested in the confirmation of the large

and? > very >? > diffuse gas coma by visual observers from dark skies.

? > >? > Best regards, >? > >? > J. J. Gonzalez Suarez >? > >? > P.S.: ? > >? > As complementary information, this is the report of my recent? observation >? > of the large dust coma of 29P : >? > >? >

29P/Schwassmann-Wachmann: >? > 2024 Dec. 27.00 UT: m1=11.1, Dia.=4', DC=2/, 20 cm SCT (77x). >? > ( Cubiellos - Sierra del Aramo, 1510 m, Asturias, Spain ) >? > >? >? > -----------------------------------------------------------------------------------------------------------

? > >? > >? > On Sat, Dec 28, 2024 at 5:39?AM Alan Hale via groups.io [email protected]> wrote: >? >? >? > > Dear Denis,

all, >? > > >? > > >? > > >? > > I’m attaching an image I took of C/2023 Q1 via LCO-Tenerife on? > December >? > > 26.97 UT (0.35-m Cassegrain, single 180-second image, unprocessed, >? > > uncropped (dimensions 30x30 arcmin)). I’ve had some trouble? > getting >? > > measurements from the image (possible software issues), but would >? > > “guesstimate” the magnitude to be somewhere around 15-15.5. I had? > not >? > > imaged the comet previously so I can’t comment about any recent? > brightening. >? > > >? > > >? > > >? > > For comparison, I’m also attaching an image I took of 29P on? > December >? > > 25.60 UT from LCO-Haleakala (0.35-m Cassegrain, single 150-second? > image, >? > > also unprocessed and uncropped, 30x30 arcmin). About eight hours? > before I >? > > took this image I observed the comet visually at m1 = 11.7, 5.5’? > coma, DC >? > > ~1 (41 cm reflector, 70x). >? > > >? > >

? > > >? > > >? > > >? > > Sincerely, >? > > >? > > Alan >? > > >? > > ? > > >? > > Hello all, >? > > >? > > I must admit I am a little

baffled by these reports of a? > substantial >? > > >? > > increase in brightness of C/2023 Q1. >? > > >? > > Firstly Thomas? Lehmann reported an increase in the brightness of? > this >? > > >? > > comet in November to mag 14.1 My observations made for astrometry? > for >? > >

? > > the months of November and December (10 nights data) show the? >

comet only >? > > >? > > increasing from mag 17 to mag 16. >? > > >? > > This is borne out by Peter Carson and Francois Kugel's comments of? > their >? > > >? > > own observations and measurements. >? > > >? > > Now JJ Gonzalez is reporting an observation on the night of Dec 27? > of >?

? > > this comet with a magnitude of 11.6. >? > > >? > > My last

observation was a day or so earlier on Dec 25 and my? > Comphot >? > >

? > > measurement gives a magnitude of 15.73 with a coma diameter of

34? > arc >? > > >? > > secs. >? > > >? > > I attach my image. >? > >

? > >? Can someone confirm the apparent +4 mag increase in brightness? or of >? > > >? > > mine, Peter Carson's and Francois Kugel's

observation results? >? > > >? > > >? > > >? > > Comets eh! >? > > >? >

? Happy NY >? > > >? > > Denis Buczynski >? > > >? > > BAA Comet

Section >? > > >? > > >? > > >? > > >? > > >? > > >? > > >? > >? ? ? ? ------ Original Message ------ >? > > >? > >? ? ? ? From: jjgsgp@... >? > > >? > >? ? ? ? To: [email protected]

? > > >? > >? ? ? ? Sent: Friday, December 27th 2024, 23:52 >? > > >? > ? ? ? ? Subject: Re: [comets-ml] Unusual brightening of comet? >

C/2023 Q1 >? > > >? > > >? > > >? > > >? > > >? > >? Thomas, all,After reading your email sent to the list yesterday,? > I >? > > >? > > have arranged an observing session for tonight. This is the report >? > > >?

:C/2023 Q1 (PANSTARRS):2024 Dec. 27.81 UT: m1=11.6, Dia.=6',? >

DC=1/, 20 >? > > >? > > cm SCT (77x).[ From dark mountain skies the comet appears visually? > much >? > > >? > > brighter than expected, showing a faint, large and very diffuse? > outer >? > > >? > > coma. Nearby field stars checked in DSS. Limiting star magnitude? > near >? >

? > > comet : 14.2 (AQ).].( Cubiellos - Sierra del Aramo, 1510 m,? >

Asturias, >? > > >? > > Spain ). All the best from the Cantabrian Mountains,J. J. Gonzalez >? > > >? > > >? > >? > Suarez--------------------------------------------------------------------------------------------------------------------------

? > > >? > > >? > > >? > > >? > > >? > >? On Fri, Dec 27, 2024 at

5:28?PM Shanklin, Jonathan D. via? > groups.io >? > > >? > > <jdsh@...> wrote: >? > > >? > >? ? ? ? ? My entry for the comet for The Astronomer magazine? > covering >? > > >? > > observations to the end of November and giving the behaviour for >? > >

? > > November was: >? > > >? > >? ? 2023 Q1 (PANSTARRS) observations

cover: -144 to -16 days, 2.6 –? > 3.0 >? > > >? > > au >? > > >? > >? ? At 17.5, steady (Carson, Pappa) >? > > >? > > >? > > >? > >? ? Which does suggest that the brightness seen in December is >? > > >? > > unexpected. >? > > >? > > >? > > >? > >? ? I won’t start putting the TA column for the next issue together? > until >? > > >? > > around January 4. >? > > >? > > >? > > >? > > >? > > >? > >? ? Regards, >? > >

? > > >? > > >? > >? ? Jonathan Shanklin >? > > >? > >? ? BAA Comet

Section visual observations co-ordinator >? > > >? > >? ? >? > > >? > > >? > > >? > > >? > > >?

? > > >? > > >? > > >? > >? ? ? From: [email protected]

<[email protected]> On Behalf Of? > Peter >? > > >? > > Carson via groups.io Sent: Friday, December 27, 2024 3:37 PM To: >? > > >? > > [email protected] Subject: [comets-ml] Unusual brightening of? > comet >? > > >? > > C/2023 Q1 >? > > >? > > >? > > >? > > >? > > >? > >

? > > >? > >? ? ? ? You don't often get email from >? > > >? > >

petercarson100@.... Learn why this is important >? > >

? > > >? > > >? > > >? > > >? > > >? > > >? > >? ? Hello Thomas, >? > > ? > > >? > > >? > >? ? Here are my observations from summer to now.

Unfortunately, I? > made >? > > >? > > no observations in October and early November, so although the? > comet has >? > > >? > > brightened, it is not? clear if the brightening occurred over a? > short or >? > >

? > > long period. >? > > >? > > >? > > >? > > >? > > >? > > >? > > >?

? ? All the best >? > > >? > > >? > > >? > >? ? Peter >? > > >? > >

? > > >? > > >? > > >? > > >? > > >? > >? ? Type Comet Obs? ? ? ? ? ? ?

? ? ? ? ? date Meth >? > > >? > > Mag Refcat Inst T App Inst F Inst P Coma User Location >? > > >? > > >? > > >? > >? ? CCD C/2023 Q1 22/12/2024 >? > > >? > > 21:11 Z 15.6 GG C 31.5 8 1260 0.80' CAR06 PGC

? > > >? > > Observatory Z10, Fregenal de la sierra, Spain >? > > >? >

? > > >? > >? ? CCD C/2023 Q1 10/12/2024 >? > > >? > > 03:18 Z 15.9

GG C 31.5 8 1200 0.80' CAR06 PGC >? > > >? > > Observatory Z10, Fregenal de la sierra, Spain >? > > >? > > >? > > >? > >? ? CCD C/2023 Q1 27/11/2024 >? > > >? > > 02:43 Z 16.1 GG C 31.5 8 1200 0.80' CAR06 PGC

? > > >? > > Observatory Z10, Fregenal de la sierra, Spain >? > > >? >

? > > >? > >? ? CCD C/2023 Q1 04/09/2024 >? > > >? > > 01:48 Z 17.5

GG C 31.5 8 1200 0.40' CAR06 PGC >? > > >? > > Observatory Z10, Fregenal de la sierra, Spain >? > > >? > > >? > > >? > >? ? CCD C/2023 Q1 16/08/2024 >? > > >? > > 03:21 Z 17.1 GG C 31.5 8 960 0.40' CAR06 PGC >?

? > > Observatory Z10, Fregenal de la sierra, Spain >? > > >? > >

? > > >? > >? ? CCD C/2023 Q1 05/08/2024 >? > > >? > > 02:33 Z 17.4 GG

C 31.5 8 960 0.40' CAR06 PGC >? > > >? > > Observatory Z10, Fregenal de la sierra, Spain >? > > >? > > >? > > >? > >? ? CCD C/2023 Q1 16/07/2024

? > > >? > > 02:52 Z 17.5 GG C 31.5 8 1080 0.40' CAR06 PGC >? > > >? > Observatory Z10, Fregenal de la sierra, Spain >? > > >? > > >? > > >?

? ? CCD C/2023 Q1 10/07/2024 >? > > >? > > 02:39 Z 17.5 GG C 31.5 8

1200 0.40' CAR06 PGC >? > > >? > > Observatory Z10, Fregenal de la sierra, Spain >? > > >? > > >? > > >? > > >? > > >? > > >? > > >? > > >?

? > > >? > > >? > > >? > > >? > > >? > > >? > > >? > > >? > >? ?

From: [email protected] <[email protected]> on behalf of? > Thomas

? > > >? > > Lehmann via groups.io <t.lehmann@...>

Sent: 26 >? > > >? > > December 2024 22:19 To: [email protected] <[email protected]> >? > > >? > > Subject: [comets-ml] Unusual brightening of comet C/2023 Q1 >? > > >? > > >? > > >? > > >? > > >? > >

? > > >? > >? ? ? According to observations by S. Fritsche and myself

the? > comet >? > > >? > > C/2023 Q1 has started a sudden brightening in November.? > Unfortunately >? > > >? > > our observations are very sparse due to the bad weather during the? > last >? > > >? > > two months. Our data suggest a brightening by 1-2 mag between? > October >?

? > > 26th and November 30th.? Latest measurement (green channel):

? > > >? > > 2024-12-23.46 UT, m1=14.1, coma diam. 5'? A more thorough? investigation >? > > >? > > by using small aperture measurements is on

the way.? Thanks to? > all >? > > >? > > contributors for sharing results and ideas/thoughts to this list.? > Merry >? > > >? > > Christmas and best wishes to all of you, Thomas >? > > >? > > >? > > >?

? > > >? > > >? > > >? > > >? > > >? > > >? > > >? > > >? > > >? >

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