开云体育

Dear all,

?

I was debating whether or not I wanted to wade into this again, but I guess my curiousity got the better of me.

?

I’m attaching two stacked versions (3 x 180 seconds) of all the images I took the other night (one positive, one inverted, i.e., negative). I have also enhanced the contrast beyond any reasonable view, and applied logarithmic scaling.

?

On those images, especially the inverted one, I can perhaps see hints of an extremely faint and vague outer coma. A generous measurement makes the diameter out to about 2 arcminutes, 2.5 arcminutes at the most.

?

I have been visually observing comets for over five decades, and have imaged dozens of comets (of a wide variety of brightnesses) via LCO over the past seven years now. Based upon that experience, there is simply no way that this outer coma on C/2023 Q1, if real – and I’ll grant for the sake of argument that it is – can be detected visually with a telescope the size of mine (41 cm) or smaller.

?

FWIW, Astrometrica measures a magnitude of 16.0, although this is primarily for the central regions.

?

And as for 29P, the comparison is definitely valid. The visual appearance was indeed very vague and diffuse (again, I measured a DC of 1). This is the same material that was contained within a coma 2 arcmin in diameter a month ago (when I measured an almost identical brightness), now spread out over a region almost six times larger in surface area.

?

?

Sincerely,

Alan

?

?

?

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 <observatorygromme=[email protected]> 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 <davefriend0=[email protected]>
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 <t.lehmann=[email protected]> 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 " <buczynski8166=[email protected]>:
>
> 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=[email protected]
>? ? ? ? To: jjgsgp=[email protected]
> 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 "?
> <jjgsgp=[email protected]>:
>? >
>? > 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
> [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=[email protected]
>? > >
>? > >? ? ? ? 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?
>
>? > >
>? > > <jdsh=[email protected]> 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 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=[email protected]. 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 <t.lehmann=[email protected]> 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
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >? ? ? This email and any attachments are intended solely for the?
> use of
>? > >
>? > > the named recipients. If you are not the intended recipient you?
> must not
>? > >
>? > > use, disclose, copy or distribute this email or any of its?
> attachments
>? > >
>? > > and should notify the sender immediately and delete? this email?
> from
>? > >
>? > > your system. UK Research and Innovation (UKRI) has taken every
>? > >
>? > > reasonable precaution to minimise risk of this email or any?
> attachments
>? > >
>? > > containing viruses or malware but the recipient should carry out?
> its own
>? > >
>? > > virus and malware checks before? opening the attachments. UKRI?
> does not
>? > >
>? > > accept any liability for any losses or damages which the recipient?
> may
>? > >
>? > > sustain due to presence of any viruses.
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >
>? > >?
>? >
>? >
>? >
>? >
>? >?
>
>
>?
>
>
>
>
>
>
>
>
>
>