Howdy Folks,
C/2024 G3 ATLAS has been kept under extensive observation by several observers, despite its poor location.
Attached a light curve showing a steady brightening toward perihelion that could see it reach magnitude -3, if it survives.
I’ve also attached images from Dec 25 and 26 showing a curious spine feature (often seen in outbursting comets) but this comet is not in outburst.
Hopefully there is sufficient nuclear material to keep going. It is a very dusty comet as seen with the parabolic hood.
This situation reminds me of C/2002 V1 NEAT in March 2023
Cheers,
Michael

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
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > 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.
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
>
>
>
>

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 <ahale=
[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













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.

?

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