Nick, that's an excellent image and I very much trust the brightness estimates
from you and Qicheng.
Don Pettit's beautiful image from space might not be appropriate to compare the
brightness of mercury and the comet as both of them might well be saturated
with mercury at much larger amount. In this case the larger extent of the
head of the comet in comparison to the (point-like) planet only gives an
illusion of much brighter appearance.
Thomas
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Am Sat, 11 Jan 2025 20:21:51 +0000 (UTC)
schrieb "Qicheng Zhang via groups.io" <qzalaska@...>:
I also just took a very quick look at the short exposure (minimally saturated) LASCO C3 data as well from Jan 11 ~12 UT. It's not possible to isolate the brightness of the coma alone, as that's <1 px in size in this camera, but within a 7 px ~ 6.5 arcmin diameter aperture, it was at V mag ~ -1.3. Note that the comet is now passing behind the (out of focus) pylon that holds the occulter in place, and the vignetting by this pylon is causing the saturation spikes in the synoptic C3 Clear data to shrink (i.e., the comet itself is not fading despite becoming less saturated on the detector).
Qicheng
On Saturday, January 11, 2025 at 11:33:02 a.m. MST, Qicheng Zhang via groups.io <qzalaska@...> wrote:
That's consistent with my initial crude estimate this morning of -0.5 (measured against Mercury earlier at a similar airmass). The comet's easy visibility is because its coma is so compact, giving it a very high surface brightness now already comparable to C/2023 A3 at its peak.
Qicheng
On Saturday, January 11, 2025 at 11:20:52 a.m. MST, Nick James <comets@...> wrote:
Maik,
Good luck tomorrow. I know you are very experienced but be careful. I'm
only risking a camera, not my eyes!
I've processed the full video now and the result is here:
I've tried to estimate the magnitude by measuring the intensity in a 40
arcsec diameter aperture and comparing it to a video of Venus taken just
before the comet observation using the same settings. Assuming Venus is
-4.6 and using a correction of 1.0 mag for differential altitude (Venus
was at 29 deg, the comet at 10 deg) I get -0.8. That doesn't really seem
bright enough given how prominent the comet is on the image but that is
what I get!
Nick.
On 11/01/2025 15:15, Maik Meyer wrote:
Nick,
this is really great, great images, thank you. I might try it visually
tomorrow as we have sunny skies predicted. Should gain maybe 2 mag in
the next 24-48 hours.
Maik
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ATLAS from the ISS, was Re: C/2024 G3 (ATLAS) from ISS
The version on Reddit had more dynamic; I could get out of it. And the later Pettit image - further processed in - reveals even more tail structure. Both of his images show two dots left and right of the comet's head: ghosts created by the ISS window? Then the central condensation would be reeeeally bright! Also of note: the great day-time image from Japan this morning ... and this 2 1/2 days before perihelion.
?
Daniel
?
Gesendet: Samstag, 11. Januar 2025 um 20:42
Von: "Matson, Rob D. via groups.io" <robert.d.matson@...>
Betreff: [comets-ml] C/2024 G3 (ATLAS) from ISS
Hi All: Here’s Don Pettit’s image from January 9th at 12:59 UT. Clearly the comet was far, far brighter at that time than Mercury (mv -0.4) to its lower left.?
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I also just took a very quick look at the short exposure (minimally saturated) LASCO C3 data as well from Jan 11 ~12 UT. It's not possible to isolate the brightness of the coma alone, as that's <1 px in size in this camera, but within a 7 px ~ 6.5 arcmin diameter aperture, it was at V mag ~ -1.3. Note that the comet is now passing behind the (out of focus) pylon that holds the occulter in place, and the vignetting by this pylon is causing the saturation spikes in the synoptic C3 Clear data to shrink (i.e., the comet itself is not fading despite becoming less saturated on the detector).
Qicheng
On Saturday, January 11, 2025 at 11:33:02 a.m. MST, Qicheng Zhang via groups.io <qzalaska@...> wrote:
That's consistent with my initial crude estimate this morning of -0.5 (measured against Mercury earlier at a similar airmass). The comet's easy visibility is because its coma is so compact, giving it a very high surface brightness now already comparable to C/2023 A3 at its peak.
Qicheng
On Saturday, January 11, 2025 at 11:20:52 a.m. MST, Nick James <comets@...> wrote:
Maik,
Good luck tomorrow. I know you are very experienced but be careful. I'm
only risking a camera, not my eyes!
I've processed the full video now and the result is here:
I've tried to estimate the magnitude by measuring the intensity in a 40
arcsec diameter aperture and comparing it to a video of Venus taken just
before the comet observation using the same settings. Assuming Venus is
-4.6 and using a correction of 1.0 mag for differential altitude (Venus
was at 29 deg, the comet at 10 deg) I get -0.8. That doesn't really seem
bright enough given how prominent the comet is on the image but that is
what I get!
Nick.
On 11/01/2025 15:15, Maik Meyer wrote: > Nick, > > this is really great, great images, thank you. I might try it visually > tomorrow as we have sunny skies predicted. Should gain maybe 2 mag in > the next 24-48 hours. > > Maik
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C/2024 G3 (ATLAS) from ISS
Hi All: Here’s Don Pettit’s image from January 9th at 12:59 UT. Clearly the comet was far, far brighter at that time than Mercury (mv -0.4) to its lower left.? --Rob
|
That's consistent with my initial crude estimate this morning of -0.5 (measured against Mercury earlier at a similar airmass). The comet's easy visibility is because its coma is so compact, giving it a very high surface brightness now already comparable to C/2023 A3 at its peak.
Qicheng
On Saturday, January 11, 2025 at 11:20:52 a.m. MST, Nick James <comets@...> wrote:
Maik,
Good luck tomorrow. I know you are very experienced but be careful. I'm
only risking a camera, not my eyes!
I've processed the full video now and the result is here:
I've tried to estimate the magnitude by measuring the intensity in a 40
arcsec diameter aperture and comparing it to a video of Venus taken just
before the comet observation using the same settings. Assuming Venus is
-4.6 and using a correction of 1.0 mag for differential altitude (Venus
was at 29 deg, the comet at 10 deg) I get -0.8. That doesn't really seem
bright enough given how prominent the comet is on the image but that is
what I get!
Nick.
On 11/01/2025 15:15, Maik Meyer wrote:
> Nick,
>
> this is really great, great images, thank you. I might try it visually
> tomorrow as we have sunny skies predicted. Should gain maybe 2 mag in
> the next 24-48 hours.
>
> Maik
|
Maik,
Good luck tomorrow. I know you are very experienced but be careful. I'm only risking a camera, not my eyes!
I've processed the full video now and the result is here:
I've tried to estimate the magnitude by measuring the intensity in a 40 arcsec diameter aperture and comparing it to a video of Venus taken just before the comet observation using the same settings. Assuming Venus is -4.6 and using a correction of 1.0 mag for differential altitude (Venus was at 29 deg, the comet at 10 deg) I get -0.8. That doesn't really seem bright enough given how prominent the comet is on the image but that is what I get!
Nick.
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On 11/01/2025 15:15, Maik Meyer wrote: Nick,
this is really great, great images, thank you. I might try it visually tomorrow as we have sunny skies predicted. Should gain maybe 2 mag in the next 24-48 hours.
Maik
|
Nick,
this is really great, great images, thank you. I might try it visually tomorrow as we have sunny skies predicted. Should gain maybe 2 mag in the next 24-48 hours.
Maik
--
"One cannot discover comets lying in bed." * Lewis Swift
________________________________________________________________________
*** @skymorph.bsky.social
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Sorry, forgot to include details. The image was taken at 1432 UTC on 2025-01-11. At that time both comet and sun were 10 deg above my horizon.
Nick.
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On 11/01/2025 15:02, Nick James wrote: I've just managed to image C/2024 G3 (ATLAS) in daylight from Chelmsford, UK (latitude 51.5N) using a 90mm refractor and an ASI1600 camera. The attached image is a differenced stack of two lots of 20x700us frames offset in declination by 23 arcmin. You can see two versions of the comet, one in positive and one in negative. The orientation is N up and the elongation is currently 7.9 deg.
The sun and comet were both low down and the sky rather hazy so I was surprised to get such a strong image. The comet must be pretty bright. I have images of Venus taken with the same settings just before so I should be able to estimate the magnitude with an appropriate correction for the different altutude.
Nick.
|
I've just managed to image C/2024 G3 (ATLAS) in daylight from Chelmsford, UK (latitude 51.5N) using a 90mm refractor and an ASI1600 camera. The attached image is a differenced stack of two lots of 20x700us frames offset in declination by 23 arcmin. You can see two versions of the comet, one in positive and one in negative. The orientation is N up and the elongation is currently 7.9 deg.
The sun and comet were both low down and the sky rather hazy so I was surprised to get such a strong image. The comet must be pretty bright. I have images of Venus taken with the same settings just before so I should be able to estimate the magnitude with an appropriate correction for the different altutude.
Nick.
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Hi Adrien/all
I reported astrometry of this comet on 2024112 from MPC Code I81 Tarbatness,however on investigation by Hirohisa Sato of the Comet Section of Oriental Astronomical Association (OAA) it turned out the the comet had been coincident with starUSNO-B1.0 1247-0142281 at mag 17.2 at the time of my observations. So the observations and astrometry are erroneous and should be deleted. Kacper Wierzchoz has been informed of this also. I did not make any detection of this comet on 20241124.I am giving this information in case any other investigator is looking at the available astrometry.
Denis Buczynski MPC I81
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------ Original Message ------ From: adrien.coffinet2@... To: [email protected] Sent: Friday, January 10th 2025, 15:21 Subject: [comets-ml] P/2024 S2 (Rankin) Hi all, CBET 5492 reports on the likely desintegration of P/2024 S2 (Rankin) www.cbat.eps.harvard.edu/iau/cbet/005400/CBET005492.txt . Adrien
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Hi all,
CBET 5492 reports on the likely desintegration of P/2024 S2 (Rankin)
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If it sticks to 7.1 + 11.7 log r it will be around -2. It is likely to be within a magnitude of that.
?
Regards,
?
Jonathan Shanklin
BAA Comet Section visual observations co-ordinator
?
?
?
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From: [email protected] <[email protected]>
On Behalf Of Matson, Rob D. via groups.io
Sent: Thursday, January 9, 2025 10:25 PM
To: [email protected]
Subject: [comets-ml] C/2024 G3 (ATLAS)
?
Hi All: Astronaut Don Pettit captured a nice image of C/2024 G3 (ATLAS) from ISS earlier today prior to one of his local sunrises. At the time of his shot (1/9 12:59 UT, Nikon Z9 lens, f/1.2, 1/60th of second)
the solar elongation was only 11 degrees. I’ll ask Don if I can share it here. Any estimate of how bright it should be right now? There are Sagittarius reference stars in his image (mu, lambda, phi, delta, gamma, eta) plus Mercury and it is far brighter than
any of them. (Mercury currently -0.4, and the comet looks at least 2 or 3 magnitudes brighter).? --Rob
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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
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Hi Terry -- I put in a request to Don to see if he can provide a raw image or images for photometry... --Rob
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-----Original Message----- From: [email protected] < [email protected]> On Behalf Of terryjlovejoy via groups.io Sent: Thursday, January 9, 2025 2:30 PM To: [email protected]Subject: EXTERNAL: Re: [comets-ml] C/2024 G3 (ATLAS) CAUTION: This email originated from outside of Leidos. Be cautious when clicking or opening content. Hi Rob, Can you ask him if he can take/share some raw images so we can do some photometric measurements? It was about mag 0, although when I observed it on Jan 8 18:40 UT it seemed to have faded just slightly. Terry On Friday 10 January 2025 at 08:24:54 am AEST, Matson, Rob D. via groups.io <robert.d.matson@...> wrote: Hi All: Astronaut Don Pettit captured a nice image of C/2024 G3 (ATLAS) from ISS earlier today prior to one of his local sunrises. At the time of his shot (1/9 12:59 UT, Nikon Z9 lens, f/1.2, 1/60th of second) the solar elongation was only 11 degrees. I’ll ask Don if I can share it here. Any estimate of how bright it should be right now? There are Sagittarius reference stars in his image (mu, lambda, phi, delta, gamma, eta) plus Mercury and it is far brighter than any of them. (Mercury currently -0.4, and the comet looks at least 2 or 3 magnitudes brighter). --Rob
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Rob,
COBS is a good source of info on comet magnitudes:
As Terry says, the latest ground based observations have it around zero. Having the raw files from Don would be great if possible so we could do some photometry.
Nick.
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On 09/01/2025 22:24, Matson, Rob D. via groups.io wrote: Hi All: Astronaut Don Pettit captured a nice image of C/2024 G3 (ATLAS) from ISS earlier today prior to one of his local sunrises. At the time of his shot (1/9 12:59 UT, Nikon Z9 lens, f/1.2, 1/60th of second) the solar elongation was only 11 degrees. I'll ask Don if I can share it here. Any estimate of how bright it should be right now? There are Sagittarius reference stars in his image (mu, lambda, phi, delta, gamma, eta) plus Mercury and it is far brighter than any of them. (Mercury currently -0.4, and the comet looks at least 2 or 3 magnitudes brighter). --Rob
|
Hi Rob,
Can you ask him if he can take/share some raw images so we can do some photometric measurements?
It was about mag 0, although when I observed it on Jan 8 18:40 UT it seemed to have faded just slightly.
Terry
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On Friday 10 January 2025 at 08:24:54 am AEST, Matson, Rob D. via groups.io <robert.d.matson@...> wrote:
??
Hi All: Astronaut Don Pettit captured a nice image of C/2024 G3 (ATLAS) from ISS earlier today prior to one of his local sunrises. At the time of his shot (1/9 12:59 UT, Nikon Z9 lens, f/1.2, 1/60th of second) the solar elongation was only 11 degrees. I’ll ask Don if I can share it here. Any estimate of how bright it should be right now? There are Sagittarius reference stars in his image (mu, lambda, phi, delta, gamma, eta) plus Mercury and it is far brighter than any of them. (Mercury currently -0.4, and the comet looks at least 2 or 3 magnitudes brighter).? --Rob
|
Hi All: Astronaut Don Pettit captured a nice image of C/2024 G3 (ATLAS) from ISS earlier today prior to one of his local sunrises. At the time of his shot (1/9 12:59 UT, Nikon Z9 lens, f/1.2, 1/60th of second) the solar elongation
was only 11 degrees. I’ll ask Don if I can share it here. Any estimate of how bright it should be right now? There are Sagittarius reference stars in his image (mu, lambda, phi, delta, gamma, eta) plus Mercury and it is far brighter than any of them. (Mercury
currently -0.4, and the comet looks at least 2 or 3 magnitudes brighter).? --Rob
|
JPL Closed Due to Fire Evacuations on Jan. 8, 2025, and to remain closed until Monday, Jan. 13 https://emergency.jpl.nasa.gov/
JPL Closed Due to Fire Evacuations on Jan. 8, 2025, and to remain closed until Monday, Jan. 13 https://emergency.jpl.nasa.gov/
|
On 2025-01-09 06:52, Fabrizio Bernardi via groups.io wrote: I was informed by a JPL colleague that JPL servers have been shut down
for obvious safety reasons due to the wildfire. At the Lab, only
emergency related personnel is present. So far, only minor issues
affected JPL, but many colleagues over there had to evacuate their
home and some, sadly, lost them, for what I know.? I was informed by a JPL colleague that the Lab (presumably, the parking lots) is also now being used as a staging ground for firefighters. If you look at this horrific picture of Altadena, the Lab is just to the left of the upper left corner. I fear that many Lab employees must have lost their homes. A sad day and a terrible tragedy. Regards Marshall Eubanks Fabrizio
Il 09/01/25 12:47, Laura Woodney via groups.io ha scritto:
JPL is inside the evacuation zone for the horrific Eaton fire. While
the currently available maps do not show it being inside the burned
region, I would not be surprised if there were no public utilities
like electric going to the campus right now - explaining why the
entire JPL website seems to be down.
It’s certain a lot of our colleagues at JPL have lost everything.
It’s very sad, and I’m sure we’ll see some crowdsourcing to
help them out appear over the next few days.
- Laura
Professor of Physics & Astronomy, CSUSB
On Jan 9, 2025, at 3:30?AM, Shanklin, Jonathan D. via groups.io
<jdsh@...> wrote:
?Maybe it's the fire.
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of
Thomas Lehmann via groups.io
Sent: Thursday, January 9, 2025 11:28 AM
To: [email protected]
Subject: [comets-ml] JPL Horizons down?
Hi all,
I am currently unable to get anything from JPL Horizons using
python3-astroquery and it looks like the JPL Solar System Dynamics
web pages are not accessible either (e.g.
;!!OM2WEIN1DMg!CZldxnCY_OOqWvmJgkWTYSXjKQ7Yt1UAz8ID96Wi5ZMBtc1ORfIF04cT1icc2OfNdVBrChs1Wr9SwkDYtdUb0xtzQgKo$
[ssd[.]jpl[.]nasa[.]gov]).
Anyone else having the same issues?
Thomas
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Re: C/2023 A3 on 2024 sep 29 at 19UT
Dear Michael, Grateful if I can ask you a question in private. My email address is vandorps@...
Best regards, Johan van Dorp
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On Sep 30, 2024, at 02:19, Michael Mattiazzo via groups.io <mmatti@...> wrote:
? Hi all, ? A3 is really starting to put on a show. The best I’ve seen since comet Lovejoy in 2011. The tail is growing rapidly. Now 10 degrees. (calculated 21 million kms and rising) By mid October this should stretch out to about 20-30 degrees. ? Perihelion +2 days C/2023 A3 Tsuchinshan-ATLAS. 2024 September 29 at 19:00UT. Canon 60Da + Canon 50mm lens. 2x30sec sec iso2000. FOV 25x35 deg. North lower left. Location: Swan Hill, Victoria, Australia.144E 35S. ? Watch a high-res animation posted on my website: ? ? A visual estimate at 19:00UT using 8x40mm binoculars was magnitude 2.5 with 4' coma and strong degree of condensation DC7, fast growing tail length now 10 degrees in PA257. Comparison stars Regulus (1.4), Nu Hydra(3.2). Comet magnitude was corrected for atmospheric extinction using the average table. Visible to the naked eye, appearing as a fuzzy star of mag 2.3, with a naked eye tail 5 degrees long. Moonlight no longer interferes. Low altitude (6 degrees) Distance to Sun = 0.39AU (59 million kms) Distance to Earth = 0.82AU (122 million kms) solar elongation = 22 degrees. ? <2023a3_20240929_1900UT_60Da_50mm_2x30sec_mmatti2c.jpg>
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Denis Buczynski
Marshall Eubanks