Keyboard Shortcuts
Likes
- Comets-Ml
- Messages
Search
Re: NEOCP object A11nyuL
¿ªÔÆÌåÓýForgot to add: image was taken on May 25.13 UT. ? Dear all, ? Here is one of the images I obtained last night from LCO-SAAO. 180-second exposure with a 35-cm Cassegrain; cropped, but otherwise no processing. ? I have another set of images ordered up for tonight. ? ? Sincerely, Alan ? Dear Krisztian, Med, all, ? It¡¯s still quite early in the game, but, indeed, this object does look interesting. There does seem to be some similarity to the orbit of the Daylight Comet of 1910, although the difference in the ascending node (as of right now, anyway), would seem to preclude a relationship. But, we¡¯ll see what the future holds . . . ? I succeeded in getting some images last night via LCO-SAAO. The appearance is almost stellar, although it does seem to be slightly diffuse when compared with stars of similar brightness. I¡¯ve reported it to the MPC (and CBAT) as a ¡°possible¡± comet. ? If something like the present orbit holds, the post-perihelion viewing geometry (when there would likely be the most dust tail development) favors the northern hemisphere. For a while, the phase angle is somewhat high, so possibly some dust tail (if there is one) enhancement from forward scattering. And ¨C yea! ¨C it¡¯s in the evening sky. On the other hand, with this small a perihelion distance, it would have to survive perihelion to put on any kind of show, and that is always problematical. ? Again, we¡¯ll just have to wait and see. I¡¯ll probably try imaging it again in a day or so. ? ? Sincerely, Alan ? Hello all , ? I know it's still too early to ask this, as the data is still uncertain, and I might be overstepping into something I don't fully understand, but I just realized that this object shares almost the same orbital elements with the Great Comet of 1910. Can you please confirm this? ? Thanks, Med ? ? On Sun, May 25, 2025, 10:23 S¨¢rneczky Kriszti¨¢n via <siraly74=[email protected]> wrote:
|
Re: NEOCP object A11nyuL
¿ªÔÆÌåÓýDear all, ? Here is one of the images I obtained last night from LCO-SAAO. 180-second exposure with a 35-cm Cassegrain; cropped, but otherwise no processing. ? I have another set of images ordered up for tonight. ? ? Sincerely, Alan ? Dear Krisztian, Med, all, ? It¡¯s still quite early in the game, but, indeed, this object does look interesting. There does seem to be some similarity to the orbit of the Daylight Comet of 1910, although the difference in the ascending node (as of right now, anyway), would seem to preclude a relationship. But, we¡¯ll see what the future holds . . . ? I succeeded in getting some images last night via LCO-SAAO. The appearance is almost stellar, although it does seem to be slightly diffuse when compared with stars of similar brightness. I¡¯ve reported it to the MPC (and CBAT) as a ¡°possible¡± comet. ? If something like the present orbit holds, the post-perihelion viewing geometry (when there would likely be the most dust tail development) favors the northern hemisphere. For a while, the phase angle is somewhat high, so possibly some dust tail (if there is one) enhancement from forward scattering. And ¨C yea! ¨C it¡¯s in the evening sky. On the other hand, with this small a perihelion distance, it would have to survive perihelion to put on any kind of show, and that is always problematical. ? Again, we¡¯ll just have to wait and see. I¡¯ll probably try imaging it again in a day or so. ? ? Sincerely, Alan ? Hello all , ? I know it's still too early to ask this, as the data is still uncertain, and I might be overstepping into something I don't fully understand, but I just realized that this object shares almost the same orbital elements with the Great Comet of 1910. Can you please confirm this? ? Thanks, Med ? ? On Sun, May 25, 2025, 10:23 S¨¢rneczky Kriszti¨¢n via <siraly74=[email protected]> wrote:
|
Re: NEOCP object A11nyuL
¿ªÔÆÌåÓýDear Krisztian, Med, all, ? It¡¯s still quite early in the game, but, indeed, this object does look interesting. There does seem to be some similarity to the orbit of the Daylight Comet of 1910, although the difference in the ascending node (as of right now, anyway), would seem to preclude a relationship. But, we¡¯ll see what the future holds . . . ? I succeeded in getting some images last night via LCO-SAAO. The appearance is almost stellar, although it does seem to be slightly diffuse when compared with stars of similar brightness. I¡¯ve reported it to the MPC (and CBAT) as a ¡°possible¡± comet. ? If something like the present orbit holds, the post-perihelion viewing geometry (when there would likely be the most dust tail development) favors the northern hemisphere. For a while, the phase angle is somewhat high, so possibly some dust tail (if there is one) enhancement from forward scattering. And ¨C yea! ¨C it¡¯s in the evening sky. On the other hand, with this small a perihelion distance, it would have to survive perihelion to put on any kind of show, and that is always problematical. ? Again, we¡¯ll just have to wait and see. I¡¯ll probably try imaging it again in a day or so. ? ? Sincerely, Alan ? Hello all , ? I know it's still too early to ask this, as the data is still uncertain, and I might be overstepping into something I don't fully understand, but I just realized that this object shares almost the same orbital elements with the Great Comet of 1910. Can you please confirm this? ? Thanks, Med ? ? On Sun, May 25, 2025, 10:23 S¨¢rneczky Kriszti¨¢n via <siraly74=[email protected]> wrote:
|
Re: NEOCP object A11nyuL
Hello all , I know it's still too early to ask this, as the data is still uncertain, and I might be overstepping into something I don't fully understand, but I just realized that this object shares almost the same orbital elements with the Great Comet of 1910. Can you please confirm this? Thanks, Med On Sun, May 25, 2025, 10:23 S¨¢rneczky Kriszti¨¢n via <siraly74=[email protected]> wrote:
|
C/2025 F2 SWAN remnant on 2025 May 16
¿ªÔÆÌåÓýHello all, ? I managed to capture the remains of disintegrated comet C/2025 F2 SWAN. Attached image was taken on 2025 May 16 at 23:00UT using a remote telescope in Chile, ASAN250 f/3.8 + ASI6200mm 4x60sec. FOV 30'. North right. The debris field stretches at least 10' NE from the ephemeris position and appears of approximate magnitude 13-14. ? cheers, Michael |
Re: comet 29P in outburst
Following the most recent outburst the coma is developing as the comet fades. Regards, Wayne On Sat, 17 May 2025 at 22:54, Nicolas Delaunoy via <delaunoyn=[email protected]> wrote:
|
comet 29P in outburst
Hi all, Comet 29P/Schwassmann-Wachmann is most likely in a strong outburst. I imaged this comet earlier today and noticed a condensed inner coma of 0.4' in diameter with classic outburst appearance. Outer coma is large and very diffuse. Total magnitude measured is m1=12.4:, dust production rate is huge Af(Rho)=20336¡À678 cm. Comet 29P/Schwassmann-Wachmann 2025 May 16.20 UT ?inner coma dia.=0.4' m1=13.7; outer coma dia.=&4.1' m1=12.4: (m2=14.4)... [T11] 0.51-m f/4.5 Corrected Dall-Kirkham + CCD... iTelescope observatory, U94 (remotely from Great Basin Desert, Beryl Junction, Utah, USA) Image is attached. Please, confirm! best regards, Taras |
Re: BAA Comet and Meteor Section meeting, Edinburgh, Saturday, October 4th
Hi Manos,
toggle quoted message
Show quoted text
Thanks. Yes, I hope that it will be recorded and made available online after the meeting. Nick. On 13/05/2025 09:27, Manos Kardasis via groups.io wrote:
Hello, thanks for informing us. Very nice program with interesting talks! Unfortunately too far from me in Athens :) |
Re: BAA Comet and Meteor Section meeting, Edinburgh, Saturday, October 4th
Hello, thanks for informing us. Very nice program with interesting talks! Unfortunately too far from me in Athens :) I am so impressed that will be held in a church! Wish you all have nice time in the meeting. Will it be online sometime in the future? Manos Kardasis https://kardasis.weebly.com/comets.html ¦²¦Ó¦É? ¦³¦Ñ?¦Ó¦Ç 13 ¦¬¦Á?¦Ï¦Ô 2025 ¦Ò¦Ó¦É? 09:31:16 ¦Ð.¦Ì. EEST, ¦Ï ¦Ö¦Ñ?¦Ò¦Ó¦Ç? Nick James <comets@...> ?¦Ã¦Ñ¦Á¦×¦Å: The British Astronomical Association will be holding a joint meeting of its Comet and Meteor sections in Edinburgh on Saturday, 4th October, 2025. You can find a list of topics and speakers at the following link: The meeting is open to everyone interested in comets and meteors. You don't need to be a BAA member to come along, although we might try to persuade you to join on the day! We are using Ticket Tailor for booking. The direct link to the booking form is: Accommodation can be eye-wateringly expensive in central Edinburgh but the venue is within walking distance of train and bus stations and there are many cheaper accommodation options further out. Nick James. BAA Comet Section. |
BAA Comet and Meteor Section meeting, Edinburgh, Saturday, October 4th
The British Astronomical Association will be holding a joint meeting of its Comet and Meteor sections in Edinburgh on Saturday, 4th October, 2025. You can find a list of topics and speakers at the following link:
The meeting is open to everyone interested in comets and meteors. You don't need to be a BAA member to come along, although we might try to persuade you to join on the day! We are using Ticket Tailor for booking. The direct link to the booking form is: Accommodation can be eye-wateringly expensive in central Edinburgh but the venue is within walking distance of train and bus stations and there are many cheaper accommodation options further out. Nick James. BAA Comet Section. |
Re: Comet of the century or pipe dream?
¿ªÔÆÌåÓýDear Maik, all, ? I concur that, given the circumstances, it was appropriate to stop the investigation at that point. ? Indeed, the discrepancy between the Chinese and Roman reports of the 44 B.C. is ¡°worrisome.¡± But given the political goings-on in Rome at the time ¨C especially if these records were made years, if not decades, after the fact ¨C I would tend to treat any details in the Roman records with at least some suspicion. (And, given how easy it is even in the here-and-now for politicians to manipulate scientific data for their own purposes, and how many people in the general public will accept this unconditionally, it is quite easy to believe that such a process could have taken place in ancient Rome.) While I¡¯m reasonably certain that a bright comet was indeed observed from Rome during 44 B.C. not too long after the assassination of Julius Caesar, anything else is, at the very least, clouded in uncertainty. ? If the comet really does return in 2097, it might possibly be observed long enough such that some of these issues could be cleared up. But, as I and others here have lamented, few, if any, of us here will be around at the time to see this happen. ? ? Sincerely, Alan ? Alan, David,
07.05.2025 01:30:37 Alan Hale <ahale@...>:
|
Re: Comet of the century or pipe dream?
¿ªÔÆÌåÓýAlan, David,I am currently on travel, so please forgive me this short answer. First, please bear in mind that the projected perihelion dates are already quite uncertain in 336 and even more in -43. If you look at the table which gives the perihelion dates by varying the date in 1402, you'll notice that the range of dates for the apparition around the year BC/AD is very large. Add to that that there are possibly non- gravitational forces, too. So, while it seems exciting to have ended up in -43 I would be careful about its certainty. And this is also the reason that I did not look any further in the past as the dates and the records itself are extremely uncertain and everything would be just a speculation. Second, my biggest gripe with the records from -43 is that the Chinese apparently did not see the daylight comet which was allegedly seen from Rome. Usually it's the other way round. If the -43 observations would have been fitting I would've looked further, probably. But the facts told me to stop there. Regards Maik Sent from my mobile 07.05.2025 01:30:37 Alan Hale <ahale@...>:
|
Re: Comet of the century or pipe dream?
¿ªÔÆÌåÓýHi David, all, ? Interesting thoughts. When I was researching this object some years ago I came across the opposite speculation, i.e., it was the Roman dates that are incorrect. (I honestly don¡¯t recall where I read that, but I included it in my I&S20 discussion about this comet.) If one thinks about it, it does seem to be an interesting coincidence that the comet¡¯s appearance just happened to coincide with the Ludi Victoriae Caesaris festival. As I wrote it ¨C again, I don¡¯t remember the source ¨C ¡°. . . some scholars even venturing the idea that the comet¡¯s ¡®appearance¡¯ during the Roman festival was nothing more than an after-the-fact propaganda ploy developed by Octavian and/or his associates.¡± Since some of this ¡°dating¡± apparently took place several years later, an intentional ¡°re-dating¡± would seem to be at least conceivable, especially given the political situation in Rome at the time. ? I agree that it is very unlikely, although certainly not impossible, that two bright comets happened to appear during 44 B.C. However, for this to be the case that would mean that the Chinese and Korean astronomers, who were apparently quite meticulous sky-watchers, would have missed one, one that the common people in Rome easily saw. ? Unless this business with the conflicting records can be sorted out, this may be one of those historical mysteries that are never resolved. As I wrote a few years ago, ¡°Whatever might have really happened would seem to be lost within the mists of time.¡± ? ? The relevance of this discussion is predicated on the idea that Maik and Gary are correct in their identification of the comet of 1744 with the earlier historical comets. My own feeling is that they make a pretty good case, but there is probably no way to know for sure one way or the other until the appointed date (i.e., 2097) gets here. And, especially given the health issues I have experienced during recent years, I somehow don¡¯t think I¡¯ll make it to the ripe old age of 139. If the identity really is correct then it might well be recovered several years prior to that, and I¡¯ve enjoyed the discussion here about Webb or some similar telescope looking for it many years in advance, but I tend to agree with the overall consensus that there probably won¡¯t be any dedicated search attempts for quite a while ¨C much too far in the future to do me any good, alas. ? One additional thought that occurred to me . . . if the identity is correct, and the comet (or one of the two comets) of 44 B.C. is really this comet, then what about the return prior to that? I don¡¯t¡¯ know if Maik and Gary looked at this . . . and all I have are secondary and tertiary sources. There does seem to have been a fairly bright comet in 426 B.C. that was observed in both the Orient and from Athens, although at least from the information I¡¯ve read there isn¡¯t enough in the way of positional information to tell much about it. There was a possible comet seen in Athens in 430 B.C. and apparently one seen from the Orient in 433 B.C. This is really just a ¡°quick look¡± on my account, and Gary and/or Maik and/or others may know much more about these objects than I do. ? ? Sincerely, Alan ? Hi Maik and all, I have been thinking about the Great Comet of -43 and the possibility that it was a return of the 1744 comet.? If you are correct about the orbit of this latter object (and you certainly make a good case in my opinion) and the comet returned around the middle of -43, it seems strange that it would have passed by unrecorded. True, the apparition would not have been a good one, but with the very bright intrinsic magnitude of this object, it is unlikely that it would not have been seen. It is also unlikely that, at the same time, another bright comet appeared (though not ipossible of course). The Chinese observations note that this comet was "reddish-yellow" in colour, presumably due to sodium boiling out from dust particles. This implies that the comet was large, dusty and relatively close to the Sun. It also suggests that it was bright enough for a definite colour to be perceived.? My question is whether the Chinese dates could be incorrect. As you point out, there are some difficulties with the records (the comet could not have been in Orion, for instance) and all the records were composed well after the event itself. Is it possible that the Chinese observations were given the wrong date? It would not be the only time that this happened in ancient Chinese chronicles, at least, as their translations have come down to us. Assuming a perihelion date at the end of July, if the Chinese observations were made during July instead of June, the fit both with the Roman comet and the computed return of 1744 seem to be better, I think. Unfortunately, I do not have a program that can handle such early dates, but as best as I can determine, the comet would indeed have been in the NW sky in the middle of July, with a tail most likely pointing toward the NE as recorded. It would have been deep in twilight, but bright enough to be conspicuous, especially if it displayed a bright dust tail. Indeed, the relatively modest length of the recorded tail (5 - 10 degrees) might even suggest that the observations were made in twilight, with the fainter extremities of the tail being invisible against a bright sky. The Chinese and Roman observations may overlap as the comet drifted further into twilight but became brighter. As seen in Rome, the comet became visible some time during the hour before sunset, at small elngation and setting soon after the Sun. There is no indication that the comet was visible at night. This is just a suggestion and I realize that it could be criticized as altering the data to fit the hypothesis. But I simply suggest it as a possible line of thought. Cheers, David ? ? ?
? |
Re: Comet of the century or pipe dream?
Hi Maik and all, I have been thinking about the Great Comet of -43 and the possibility that it was a return of the 1744 comet.? If you are correct about the orbit of this latter object (and you certainly make a good case in my opinion) and the comet returned around the middle of -43, it seems strange that it would have passed by unrecorded. True, the apparition would not have been a good one, but with the very bright intrinsic magnitude of this object, it is unlikely that it would not have been seen. It is also unlikely that, at the same time, another bright comet appeared (though not ipossible of course). The Chinese observations note that this comet was "reddish-yellow" in colour, presumably due to sodium boiling out from dust particles. This implies that the comet was large, dusty and relatively close to the Sun. It also suggests that it was bright enough for a definite colour to be perceived.? My question is whether the Chinese dates could be incorrect. As you point out, there are some difficulties with the records (the comet could not have been in Orion, for instance) and all the records were composed well after the event itself. Is it possible that the Chinese observations were given the wrong date? It would not be the only time that this happened in ancient Chinese chronicles, at least, as their translations have come down to us. Assuming a perihelion date at the end of July, if the Chinese observations were made during July instead of June, the fit both with the Roman comet and the computed return of 1744 seem to be better, I think. Unfortunately, I do not have a program that can handle such early dates, but as best as I can determine, the comet would indeed have been in the NW sky in the middle of July, with a tail most likely pointing toward the NE as recorded. It would have been deep in twilight, but bright enough to be conspicuous, especially if it displayed a bright dust tail. Indeed, the relatively modest length of the recorded tail (5 - 10 degrees) might even suggest that the observations were made in twilight, with the fainter extremities of the tail being invisible against a bright sky. The Chinese and Roman observations may overlap as the comet drifted further into twilight but became brighter. As seen in Rome, the comet became visible some time during the hour before sunset, at small elngation and setting soon after the Sun. There is no indication that the comet was visible at night. This is just a suggestion and I realize that it could be criticized as altering the data to fit the hypothesis. But I simply suggest it as a possible line of thought. Cheers, David
|
Re: Comet of the century or pipe dream?
Quicheng,
I'm crudely estimating from the posted uncertainties that the 3¦Ò uncertainty ellipse is somewhere around 20 arcmin across, which is rather large for JWST whose largest camera only covers a pair of 2.2x2.2 arcmin fields.thank you very much for the technical background! Yes, that's a rather small FOV for the JWST. I guess I should work to get an executive order once the NGRST has seen first light... 8-) Maik -- "One cannot discover comets lying in bed." * Lewis Swift ________________________________________________________________________ |
Re: Comet of the century or pipe dream?
I'm crudely estimating from the posted uncertainties that the 3¦Ò uncertainty ellipse is somewhere around 20 arcmin across, which is rather large for JWST whose largest camera only covers a pair of 2.2x2.2 arcmin fields. The full ellipse still about fits within a single Roman field, and that telescope should be about as sensitive as Hubble = only ~1-2 mag less sensitive than JWST for the same exposure time (which should make actually Roman faster at searching the full field to the same depth). However, given that solar system science is an extremely low priority for that telescope, I doubt a dedicated search program that goes sufficiently deep for a realistic chance of detection (likely taking a few days) would ever be approved. I think the best chance here would be to find a team with a non-solar system science case to do a deep observation of a field that fits the characteristics of the comet search field, and ask them to target that search field for their program. Qicheng
On Sunday, May 4, 2025 at 07:31:54 a.m. MST, Adrien Coffinet via groups.io <adrien.coffinet2@...> wrote:
Mag 34 for JWST is ultra-deep field like when Hubble reaches mag 31+. I'm not convinced that they would make such an ultra-deep field just to recover such a comet that would anyway be recovered long before perihelion by more classical telescopes, unless one really has a good reason for such an observation, or has something else more certain to observe in this field. Adrien Le dim. 4 mai 2025, 16:12, Maik Meyer via <maik=[email protected]> a ¨¦crit?: Thanks Rob! |