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Comete C2019Y4 ATLAS UVEX g1200
Posted: Mon Apr 06, 2020 8:45 am
by Dubreuil Pierre
Bonjour à tous
Après une premiere tentative le 4/04 j'ai tenté de nouveau la comète avec aide et remarques de Christian Buil.
Poses de 1200s au lieu de 600s.
Le panneau d'acquisition cette nuit:
- acquisitions cette nuit
J'ai aussi repris mon soft de guidage sur fente qui m'a enfin permis de guider 2h sans voir la comète sortir de la fente !
Quelques détails dans la raie 4880 CN mais je n'ai pas les compétences pour l'identification.
La comparaison de deux nuits:
- Comete sur 2 nuits
Zoom région Cn 4880:
- ZOOM zone CN 4880A
- compare_cometeZOOM.png (135.93 KiB) Viewed 6722 times
Image 300s avec Lunette chercheur (pour le fun !):
- Chercheur
- imageBrute300sLunetteChercheur.png (403.9 KiB) Viewed 6722 times
Sacrée comète, très faible pour ma config... !
Pierre
Re: Comete C2019Y4 ATLAS UVEX g1200
Posted: Mon Apr 06, 2020 11:39 am
by Jean-Pierre Masviel
Pierre, pour t'aider à indentifier les raies, tu as la page de M. Brown:
http://web.gps.caltech.edu/~mbrown/comet/
Using high-resolution spectra obtained with the Hamilton echelle spectrograph at Lick Observatory, we have constructed a catalogue of emission lines observed in comets Swift-Tuttle and Brorsen-Metcalf. The spectra cover the range between 3800 and 9900 A with a spectral resolution of ~ 42000. In the spectra, we catalogue 2997 emission lines of which we identify 2437. We find cometary lines due to H, O, C2, CN, NH2, C3, H2O+, CH, and CH+. We list 559 unidentified lines compiled from the two spectra.
Jean-Pierre
Re: Comete C2019Y4 ATLAS UVEX g1200
Posted: Tue Apr 07, 2020 9:27 am
by Michel Verlinden
Bravo Pierre, vraiment pas facile cette cible, elle n'est pas très brillante.
Une modification de la structure de l'objet est rapportée dans les ATEL. Possible amorce de désintégration amorcée depuis quelques jours.
http://www.astronomerstelegram.org/?read=13622
Image de la comète dans la nuit du 4 au 5 avril. Filtre clair. Addition des images alignées sur les étoiles.
2 queues ? 2 noyaux ? Artéfact ?
Amicalement,
Michel Verlinden
Re: Comete C2019Y4 ATLAS UVEX g1200
Posted: Tue Apr 07, 2020 1:56 pm
by Dubreuil Pierre
Merci Jean-Pierre pour l'identification. En fait la raie 3880 est large mais que tu CN !
Merci Michel, aussi je vérifierai ce soir si je vois aussi un dédoublement, donc 2 comètes !
Pierre
Re: Comete C2019Y4 ATLAS UVEX g1200
Posted: Tue Apr 07, 2020 2:47 pm
by Robin Leadbeater
Michel Verlinden wrote:Bravo Pierre, vraiment pas facile cette cible, elle n'est pas très brillante.
Une modification de la structure de l'objet est rapportée dans les ATEL. Possible amorce de désintégration amorcée depuis quelques jours.
http://www.astronomerstelegram.org/?read=13622
Image de la comète dans la nuit du 4 au 5 avril. Filtre clair. Addition des images alignées sur les étoiles.
2 queues ? 2 noyaux ? Artéfact ?
Nick James, (BAA comet section director) has just posted some measurements showing a small change in orbit suggesting either a break up or significant increase in outflowing material. He is also seeing a more diffuse coma
https://britastro.org/node/21355
Re: Comete C2019Y4 ATLAS UVEX g1200
Posted: Wed Apr 08, 2020 1:24 pm
by David Boyd
Here is a comparison of two spectra of C/2019 Y4 (ATLAS) taken with a LISA on a C11. These are integrations of 130 and 90 mins respectively. The spectrum on 26 March was taken just before the recent disruption of the comet noted by several observers, the spectrum on 6 April was taken after. Reports indicate that the event has reduced the brightness of the comet by about a magnitude and it has become more diffuse. This was apparent from the increased difficulty in guiding on the comet in the later spectrum. The later spectrum also suffers from greater noise beyond that expected just from the reduced exposure time. However, it appears that the event has not introduced any significant change in the spectral profile of the comet.
David
- C2019 Y4 (ATLAS) 26 March + April 6 2020.png (84.2 KiB) Viewed 6610 times
Re: Comete C2019Y4 ATLAS UVEX g1200
Posted: Fri Apr 10, 2020 8:30 am
by Dubreuil Pierre
David Boyd wrote:Here is a comparison of two spectra of C/2019 Y4 (ATLAS) taken with a LISA on a C11. These are integrations of 130 and 90 mins respectively. The spectrum on 26 March was taken just before the recent disruption of the comet noted by several observers, the spectrum on 6 April was taken after. Reports indicate that the event has reduced the brightness of the comet by about a magnitude and it has become more diffuse. This was apparent from the increased difficulty in guiding on the comet in the later spectrum. The later spectrum also suffers from greater noise beyond that expected just from the reduced exposure time. However, it appears that the event has not introduced any significant change in the spectral profile of the comet.
David
The attachment C2019 Y4 (ATLAS) 26 March + April 6 2020.png is no longer available
Belle comparaison David
Je confirme que la chute de luminosité est flagrante et il est pratiquement impossible de guider sur le noyau, ce que j'ai essayé de faire à la limite du décrochage, et pas toujours parfaitement ( passage étoiles proches du noyau).
Ci-dessous le champs du capteur de guidage posé 20s gain maxi caméra ZWO290MM. (poses 6s pendant guidage noyau)
- champs Guidage 20s
La comète (très bruitée, posée 6x1200s)
- comete 6x1200s
- Comete_3732 to 4381.png (141.48 KiB) Viewed 6564 times
- zoom 3880 A
- Comete_Zoom.png (101.49 KiB) Viewed 6564 times
Pierre