Re: Is C/2024 M1 really a comet?
Nicolas,
?
Don't apologize, you put a lot of time and effort into collecting and processing these images, providing data for others who don't have such information to scrutinize. One can look at any image, any camera, any telescope, any software processing, anything to do with imaging comets and find numerous things to suggest the data is not perfect. Anyone who thinks any data is perfect is only fooling themselves. The only comet data that comes close to being perfect data is a single image that has had nothing done to it, totally raw data. Your data has created a lot of discussion which is a good thing, everyone should look at their own data and ask themselves just how realistic is that data after all the processing and everything else that has been done to their images. Then one can ask what the atmospheric conditions were when those images were collected from the surface of Planet Earth. Smog, thin clouds, haze, light pollution, aluminum oxide and the list goes on and on, a list that no one can answer but which produces or hides artifacts such as comas. Magnitude estimates, coma size, comas, tail lengths, everything to do with comet observations depends on so many variables that it is hard to decide if your images did show cometary activity, but it is also hard to say that they did not.
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Re: uncertainty of CMOS vs CCD observations
Thank you all for your replies! This is more or less what I expected, but now I feel more confident after having independent confirmation from people with direct experience on the topic.
Happy holidays!
Federico
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Re: Is C/2024 M1 really a comet?
Hello to all,
Despite all the care I take for my shots, do not forget that the telescope used is only a connected telescope, powerful it is true but also has its flaws. For the magnitude calculation I am about consistent with other observers but you should not ask too much of it! What you see in the photo is probably an artifact so to take "with tweezers".?
Thank you and merry Christmas to all.
?
Bonjour ¨¤ toutes et ¨¤ tous,
Malgr¨¦ tous les soins que je prends pour mes prises de vue, n'oubliez pas que le t¨¦lescope utilis¨¦ n'est qu'un t¨¦lescope connect¨¦, performant il est vrai mais qui a aussi ses d¨¦fauts. Pour le calcul de magnitude je suis ¨¤ peu pr¨¨s coh¨¦rents avec les autres observateurs mais il ne faut pas trop lui en demand¨¦ ! Ce que vous voyez sur la photo est probablement un artefact donc ¨¤ prendre "avec des pincettes".?
Merci et joyeux no?l ¨¤ toutes et ¨¤ tous.
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Re: Is C/2024 M1 really a comet?
Mike - you are right that there's no clear objective dividing line between 'comet' and 'asteroid', and that the current definition is somewhat arbitrary, but this is still the definition we are working under until we can make some more quantifiable measure of activity level for solar system objects.
Regardless of if C/2024 M1 has a few kg/s of activity, its activity is clearly lower than a normal comet (below detectable levels) and should follow the precedent set by other damocloids. We are recording objects as comets based on activity, not based on feeling cometary based on their orbit alone, along with possible confirmation bias as I suspect happened here with the initial reports.
Reinder - Nicolas's observation does not seem to be perfectly stacked or may have some degree of (telescopic) coma. Surrounding stars clearly are fuzzier on the upper left than on the lower right direction and I suspect a sidereal stack would show each of them to have the same feature. Also, at the quoted 1.32" pixel scale this tail would be 8" long, which is quite a bit larger than other simultaneous observations rule out. Not to mention the fact that the observed tail seems to be of constant brightness and abruptly stop 8" from the nucleus, which is odd on its own.
~Sam
On Tuesday, December 24, 2024 at 03:01:40 PM EST, Mike Olason via groups.io <molason@...> wrote:
If one wants to be honest about what happens to any object with basically no atmosphere that gets close enough to the Sun to heat up its surface, they are all comets according to our definition of comets, even if we can't see the ejected material. That intense radiation heat is going to result in the ejection of material off the surface of such objects, the only limiting factor is whether our telescopes and cameras can see the objects that don't eject very much material so we humans can call them a comet or not. An asteroid is either an almost burnt-out comet or an object waiting to become a comet depending on its orbit. If one is lucky enough to catch one of these rather non-active objects when it happens to eject a little material due to the intense solar radiation falling on the right spot on its surface at the right time and get an image of that activity, then we humans call it a comet. Everything is subjective, even determining what is or isn't a comet, based on our own limitations of observation and the timing of such observations. As always, the truth is in the eye of the beholder.
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Re: Is C/2024 M1 really a comet?
IMHO The level of activity is the important factor for the asteroid orbit study. If it is an object with so low activity that doesn¡¯t affect observations is not a comet-like object. With no outburst and no non-gravitational effects. To recover objects after some oppositions the main factor to conclude that the object disappeared or simply is faint is if follows a comet like curve or the ejecta have influenced the orbit
If the object is in a comet like orbit at i>30 and high eccentricity is still an asteroid and there are many examples. Even if it could be considered a dead comet or near low emission comet.?
Following what you said I think many of that objects in that kind objects that doesn¡¯t appear like originated in the MB or planetary disc, but in Oort Cloud, should be redefined or given a new classification.
Sincerely,
El El mar, 24 de diciembre de 2024 a la(s) 14:01, Mike Olason via <molason= [email protected]> escribi¨®:
If one wants to be honest about what happens to any object with basically no atmosphere that gets close enough to the Sun to heat up its surface, they are all comets according to our definition of comets, even if we can't see the ejected material. That intense radiation heat is going to result in the ejection of material off the surface of such objects, the only limiting factor is whether our telescopes and cameras can see the objects that don't eject very much material so we humans can call them a comet or not. An asteroid is either an almost burnt-out comet or an object waiting to become a comet depending on its orbit. If one is lucky enough to catch one of these rather non-active objects when it happens to eject a little material due to the intense solar radiation falling on the right spot on its surface at the right time and get an image of that activity, then we humans call it a comet. Everything is subjective, even determining what is or isn't a comet, based on our own limitations of observation and the timing of such observations. As always, the truth is in the eye of the beholder.
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Re: Is C/2024 M1 really a comet?
If one wants to be honest about what happens to any object with basically no atmosphere that gets close enough to the Sun to heat up its surface, they are all comets according to our definition of comets, even if we can't see the ejected material. That intense radiation heat is going to result in the ejection of material off the surface of such objects, the only limiting factor is whether our telescopes and cameras can see the objects that don't eject very much material so we humans can call them a comet or not. An asteroid is either an almost burnt-out comet or an object waiting to become a comet depending on its orbit. If one is lucky enough to catch one of these rather non-active objects when it happens to eject a little material due to the intense solar radiation falling on the right spot on its surface at the right time and get an image of that activity, then we humans call it a comet. Everything is subjective, even determining what is or isn't a comet, based on our own limitations of observation and the timing of such observations. As always, the truth is in the eye of the beholder.
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Re: Is C/2024 M1 really a comet?
After checking, just artifact!
Le 24/12/2024 ¨¤ 12:56, Francois KUGEL
via groups.io a ¨¦crit?:
Hello Sam ,
My observations from Nov. 04 and Dec. 12 seem to show to jets
in PA 200 and 340¡ã?
but maybe it is just artefacts :
Best regards,
Francois
Le 24/12/2024 ¨¤ 00:12,
planetaryscience via groups.io a ¨¦crit?:
Hi all,
I wanted to invite some
discussion on this topic I've been wondering about for a
bit: I don't think C/2024 M1 is actually a comet.
C/2024 M1 (ATLAS) was
published as a comet back in July, with four reports of
cometary activity from X07 (H. Sato, T. Yoshimoto, and T.
Prystavski) and W88 (N. Paul) - ~0.25 and ~0.5-m telescopes.
Meanwhile, my own simultaneous observations from X09 (0.43m)
did not detect any sign of coma or tail even on extended
exposures far outdoing the 15x50s (750s) exposure of N.
Paul, the longest stack searching for cometary activity
among the positives reported.
Similarly, no images that
I've seen published by Seiichi Yoshida on aerith.net show
even slight hints of coma or tail, even with significant SNR
on the body. The 'comet's light curve has followed an
asteroidal 5logr light curve from 8.6 AU from the Sun all
the way through its 1.7 AU perihelion in October, as well as
its peak magnitude of V=14 a few weeks ago.
I'm not sure what the three
itelescope and one slooh observers saw, but I think I have
to guess that they all made a mistake. Nothing I've seen
firsthand (including the attached very high-SNR
observation by a friend a few days ago) supports
these claims, and I'm considering requesting the MPC to
redesignate it as an A/ object.
~Sam
--
Francois KUGEL
Observatoire chante-perdrix
Dauban
04150 BANON - France
MPC station # A77
--
Francois KUGEL
Observatoire chante-perdrix
Dauban
04150 BANON - France
MPC station # A77
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Re: Is C/2024 M1 really a comet?
Hello Sam ,
My observations from Nov. 04 and Dec. 12 seem to show to jets in
PA 200 and 340¡ã?
but maybe it is just artefacts :
Best regards,
Francois
Le 24/12/2024 ¨¤ 00:12, planetaryscience
via groups.io a ¨¦crit?:
Hi all,
I wanted to invite some
discussion on this topic I've been wondering about for a bit:
I don't think C/2024 M1 is actually a comet.
C/2024 M1 (ATLAS) was
published as a comet back in July, with four reports of
cometary activity from X07 (H. Sato, T. Yoshimoto, and T.
Prystavski) and W88 (N. Paul) - ~0.25 and ~0.5-m telescopes.
Meanwhile, my own simultaneous observations from X09 (0.43m)
did not detect any sign of coma or tail even on extended
exposures far outdoing the 15x50s (750s) exposure of N. Paul,
the longest stack searching for cometary activity among the
positives reported.
Similarly, no images that
I've seen published by Seiichi Yoshida on aerith.net show even
slight hints of coma or tail, even with significant SNR on the
body. The 'comet's light curve has followed an asteroidal
5logr light curve from 8.6 AU from the Sun all the way through
its 1.7 AU perihelion in October, as well as its peak
magnitude of V=14 a few weeks ago.
I'm not sure what the three
itelescope and one slooh observers saw, but I think I have to
guess that they all made a mistake. Nothing I've seen
firsthand (including the attached very high-SNR
observation by a friend a few days ago) supports
these claims, and I'm considering requesting the MPC to
redesignate it as an A/ object.
~Sam
--
Francois KUGEL
Observatoire chante-perdrix
Dauban
04150 BANON - France
MPC station # A77
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Re: Is C/2024 M1 really a comet?
Op 24-12-2024 om 0:12 schreef
planetaryscience via groups.io:
Hi all,
I wanted to invite some
discussion on this topic I've been wondering about for a bit:
I don't think C/2024 M1 is actually a comet.
C/2024 M1 (ATLAS) was
published as a comet back in July, with four reports of
cometary activity from X07 (H. Sato, T. Yoshimoto, and T.
Prystavski) and W88 (N. Paul) - ~0.25 and ~0.5-m telescopes.
Meanwhile, my own simultaneous observations from X09 (0.43m)
did not detect any sign of coma or tail even on extended
exposures far outdoing the 15x50s (750s) exposure of N. Paul,
the longest stack searching for cometary activity among the
positives reported.
Similarly, no images that
I've seen published by Seiichi Yoshida on aerith.net show even
slight hints of coma or tail, even with significant SNR on the
body. The 'comet's light curve has followed an asteroidal
5logr light curve from 8.6 AU from the Sun all the way through
its 1.7 AU perihelion in October, as well as its peak
magnitude of V=14 a few weeks ago.
I'm not sure what the three
itelescope and one slooh observers saw, but I think I have to
guess that they all made a mistake. Nothing I've seen
firsthand (including the attached very high-SNR
observation by a friend a few days ago) supports
these claims, and I'm considering requesting the MPC to
redesignate it as an A/ object.
~Sam
Hi Sam, all
It is definitely a (periodic) comet albeit one with very low
activity.
See this superb image obtained on December 19 by Nicolas Delanoy:
Note the soft tones that bring out the very faint coma/tail in the
magnified image.
Best regards,
??? Reinder
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Re: Is C/2024 M1 really a comet?
Goodmorning,?
Well, I'm sharing the same thoughts.? I've been questioning this myself the first time i observed?this object:?
None of my observations showed any comet activity and the afrho values are always?very low. Especially when it's moving this fast i would expect to see some kind of tail or coma.?
Best Regards,
Mr. Pieter-Jan Dekelver Oudsbergen, Belgium observatorygromme@... Observatory Gr?mme - MPC: D09 ¨C M09
On Tue, Dec 24, 2024 at 1:12?AM planetaryscience via <planetaryscience= [email protected]> wrote:
Hi all,
I wanted to invite some discussion on this topic I've been wondering about for a bit: I don't think C/2024 M1 is actually a comet.
C/2024 M1 (ATLAS) was published as a comet back in July, with four reports of cometary activity from X07 (H. Sato, T. Yoshimoto, and T. Prystavski) and W88 (N. Paul) - ~0.25 and ~0.5-m telescopes. Meanwhile, my own simultaneous observations from X09 (0.43m) did not detect any sign of coma or tail even on extended exposures far outdoing the 15x50s (750s) exposure of N. Paul, the longest stack searching for cometary activity among the positives reported.
Similarly, no images that I've seen published by Seiichi Yoshida on show even slight hints of coma or tail, even with significant SNR on the body. The 'comet's light curve has followed an asteroidal 5logr light curve from 8.6 AU from the Sun all the way through its 1.7 AU perihelion in October, as well as its peak magnitude of V=14 a few weeks ago.
I'm not sure what the three itelescope and one slooh observers saw, but I think I have to guess that they all made a mistake. Nothing I've seen firsthand (including the attached very high-SNR observation by a friend a few days ago) supports these claims, and I'm considering requesting the MPC to redesignate it as an A/ object.
~Sam
|
Is C/2024 M1 really a comet?
Hi all,
I wanted to invite some discussion on this topic I've been wondering about for a bit: I don't think C/2024 M1 is actually a comet.
C/2024 M1 (ATLAS) was published as a comet back in July, with four reports of cometary activity from X07 (H. Sato, T. Yoshimoto, and T. Prystavski) and W88 (N. Paul) - ~0.25 and ~0.5-m telescopes. Meanwhile, my own simultaneous observations from X09 (0.43m) did not detect any sign of coma or tail even on extended exposures far outdoing the 15x50s (750s) exposure of N. Paul, the longest stack searching for cometary activity among the positives reported.
Similarly, no images that I've seen published by Seiichi Yoshida on aerith.net show even slight hints of coma or tail, even with significant SNR on the body. The 'comet's light curve has followed an asteroidal 5logr light curve from 8.6 AU from the Sun all the way through its 1.7 AU perihelion in October, as well as its peak magnitude of V=14 a few weeks ago.
I'm not sure what the three itelescope and one slooh observers saw, but I think I have to guess that they all made a mistake. Nothing I've seen firsthand (including the attached very high-SNR observation by a friend a few days ago) supports these claims, and I'm considering requesting the MPC to redesignate it as an A/ object.
~Sam
|
Re: uncertainty of CMOS vs CCD observations
CMOS vs. CCD shouldn't matter, nor should "estimated" uncertainty of individual astrometric positions.
What should matter is leaving out observations with bad residuals -- something that the MPC doesn't do much -- and not publishing perturbed orbits for comets with short arcs.? The MPC should only be publishing parabolic orbits for new comets that have highly elliptical orbits -- and certainly not hyperbolic solutions with 1- or 2-week arcs.
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Re: uncertainty of CMOS vs CCD observations
Either type of detector should be capable of measuring positions to a few tenths of a pixel (which will be well below 1" in most cases) with basic centroiding and a good solution to a good reference catalog.? Of course that depends on how much time the measurer devoted to the task, but CCD vs CMOS makes no difference at this level.? We achieved accuracy down to 1-2% of a pixel on the Dark Energy Camera, and this has been done by other CCD survey cameras, but I don't know if that has been achieved yet with CMOS devices.?
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Excellent! Very nice with the conjunction. I would like to know when the circular will come out, what are they waiting for? Regards, Roberto Haver 157 Frasso Sabino On Sat, 21 Dec 2024 11:46:14 -0700 "Alan Hale" <ahale@...> wrote: Dear Roberto, all,
I was able to obtain a new set of images of this object last night via LCO-Tenerife. Both single and stacked images show a small condensed coma and a distinct, straight tail up to 35 arcseconds long in approximate p.a. 285.
The attached image is a single 300-second exposure, cropped to approximate dimensions 12x12 arcminutes. The prominent galaxy is NGC 2365.
Sincerely,
Alan
Great that you confirmed. Did you send the observation with confirmation to the MPC?
Regards,
Roberto Haver
On Mon, 09 Dec 2024 12:03:25 -0700
"Alan Hale" <ahale@...> wrote:
Hi Roberto, all,
Nice job Roberto!
I can confirm that this object is exhibiting cometary behavior. On images I took yesterday with LCO-Tenerife (0.35-m Cassegrain) it is clearly showing a small condensed coma and a short westward-pointing tail. Attached image is 300-seconds, 5x5 arcminutes, standard orientation (north up, east right), taken December 8 at 23:58 UT.
Sincerely,
Alan
Object 2015 CD60 is definitely a comet.
From images taken on December 2nd (unfortunately analyzed only today) I noticed that the object 2015CD60 (object that I follow together with others to see if it has cometary activity) is definitely a comet with a tail too!
These are the data of the object:
2015CD60 Mag. 18.0 for a coma of about 10" with a tail of about 42" in PA 277¡ã.
Photo data:
Taken with a 369mm Cassegrain reduced to F/6.88 (2493mm focal length) on December 2nd 2024 (mean time 01h12m22s UT) with 46x90s and a limiting magnitude of about 22. Image scale 1".24/pixel north up but slightly tilted to the left by 4¡ã and east therefore to the left. Field of 21'.6x32'.3.
I also took it on November 1, 2024 and it showed no activity (it was even more difficult to understand due to the presence of many annoying stars nearby).
Regards,
Roberto Haver
157 Frasso Sabino
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Re: uncertainty of CMOS vs CCD observations
There should be no astrometric differences between the two types of sensors. I have used both the CCD until a couple of years ago and now a CMOS sensor and I do not see any differences due to the type of sensor. From a photometric point of view we can talk about it but even there there should be no differences (if the system is calibrated well). Regards, Roberto Haver 157 Frasso sabino On Mon, 23 Dec 2024 00:52:16 -0800 "Federico Spada via groups.io" <federico.spada@...> wrote: Hi all,
I am currently working on fitting the orbits of some long-period comets based on data obtained from the MPC database.
In assigning uncertainties to the data, my orbit fitting program follows the weighting scheme proposed by Veres et al. 2017, Icarus, 296, 139, which depends on their type, observing station, reference catalog, and, sometimes, their specific observing program.
For CCD observations, these authors recommend a conservative 1.0 or 1.5 arc seconds uncertainty, depending on whether the reference catalog is known. This weighting scheme, however, does not address observations obtained with CMOS detectors (MPC observation type code "B", as opposed to, e.g., "C" for CCD observations). Does anybody have any recommendations on how to assign the uncertainty to CMOS observations?
Best wishes,
Federico
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Re: uncertainty of CMOS vs CCD observations
I personally don't imagine why CMOS observations must have a different weighting respect to CCD observations.
Luca #204?
Il lun 23 dic 2024, 10:00 Federico Spada via <federico.spada= [email protected]> ha scritto: Hi all,
?
I am currently working on fitting the orbits of some long-period comets based on data obtained from the MPC database.
In assigning uncertainties to the data, my orbit fitting program follows the weighting scheme proposed by Veres et al. 2017, Icarus, 296, 139, which depends on their type, observing station, reference catalog, and, sometimes, their specific observing program.
For CCD observations, these authors recommend a conservative 1.0 or 1.5 arc seconds uncertainty, depending on whether the reference catalog is known. This weighting scheme, however, does not address observations obtained with CMOS detectors (MPC observation type code "B", as opposed to, e.g., "C" for CCD observations). Does anybody have any recommendations on how to assign the uncertainty to CMOS observations?
?
Best wishes,
Federico
|
uncertainty of CMOS vs CCD observations
Hi all,
?
I am currently working on fitting the orbits of some long-period comets based on data obtained from the MPC database.
In assigning uncertainties to the data, my orbit fitting program follows the weighting scheme proposed by Veres et al. 2017, Icarus, 296, 139, which depends on their type, observing station, reference catalog, and, sometimes, their specific observing program.
For CCD observations, these authors recommend a conservative 1.0 or 1.5 arc seconds uncertainty, depending on whether the reference catalog is known. This weighting scheme, however, does not address observations obtained with CMOS detectors (MPC observation type code "B", as opposed to, e.g., "C" for CCD observations). Does anybody have any recommendations on how to assign the uncertainty to CMOS observations?
?
Best wishes,
Federico
|
Dear Roberto, all, ? I was able to obtain a new set of images of this object last night via LCO-Tenerife. Both single and stacked images show a small condensed coma and a distinct, straight tail up to 35 arcseconds long in approximate p.a. 285. ? The attached image is a single 300-second exposure, cropped to approximate dimensions 12x12 arcminutes. The prominent galaxy is NGC 2365. ? ? Sincerely, Alan ? Great that you confirmed. Did you send the observation with On Mon, 09 Dec 2024 12:03:25 -0700
toggle quoted message
Show quoted text
I can confirm that this object is exhibiting cometary behavior. On images I took yesterday with LCO-Tenerife (0.35-m Cassegrain) it is clearly showing a small condensed coma and a short westward-pointing tail. Attached image is 300-seconds, 5x5 arcminutes, standard orientation (north up, east right), taken December 8 at 23:58 UT. Object 2015 CD60 is definitely a comet. From images taken on December 2nd (unfortunately analyzed only today)
I noticed that the object 2015CD60 (object that I follow together others to see if it has cometary activity) is definitely a comet These are the data of the object: 2015CD60 Mag. 18.0 for a coma of about 10" with a tail of about 42" Taken with a 369mm Cassegrain reduced to F/6.88 (2493mm focal on December 2nd 2024 (mean time 01h12m22s UT) with 46x90s and a limiting magnitude of about 22. Image scale 1".24/pixel north up but slightly tilted to the left by 4¡ã and east therefore to the left. I also took it on November 1, 2024 and it showed no activity (it was even more difficult to understand due to the presence of many
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Hi all,
MPEC 2024-Y20 announced yesterday the discovery of the Jupiter-family comet C/2024 X1 (Fazekas).
Its nominal orbital period (29.5 years) is surprisingly similar to that of Saturn (29.4 years; and also to 2.5 times that of Jupiter, 29.7 years), but note the uncertainty (+/- 2.8 years), so more observations will be needed before any resonance check can be done.
More anecdotally, you'll note that it has a C/ prefix despite its nominal orbital period being (slightly) below 30 years.
Adrien
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Re: KOPR APASS catalog magnitudes issues?
Hi Jakub,
?
1. It is really the isue with the query looking from the comet center instead of the center of the image.
If you have in the settings the option calculated comet pos. ON then the queries seem to be done from that point out insted of the CRVAL1 and CRVAL2 from the header of the image.
I solved that by commenting out two lines of the code.
I have also solved the online catalog issue. That was related to my chang of the WorldtoPix function that was making issues with my mathplotlib and KOPR would not load the images. But now that modification caused the parsing of the star catalog to stop working.
?
2. Could actually be the difference between the APASS v9 (vizier query) and APASS v10 (local copy).
?
Thank you for your support
Best regards
Jure
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Mike Olason
reinder j bouma
