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
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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 ¨C 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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