Affiliation
American Association of Variable Star Observers (AAVSO)
Thu, 10/26/2023 - 20:46
Alert Notice 838 announces the targets and approximate schedule for the third year of the HST CV observing campaign by Pala et al. Please see the notice for details and observing instructions.
There are threads for this campaign under the following AAVSO forums:
- Campaigns and Observing Reports: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024
- Cataclysmic Variables: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024-01
Please subscribe to these threads if you are participating in the campaign so you can be updated, ask questions, and join in the discussion!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ
Alert Notice 839 announces the HST observing schedule on 2023 November 10 for the cataclysmic variable BF Eri. Please see the notice for details and observing instructions.
There are threads for this campaign under the following AAVSO forums:
- Campaigns and Observing Reports: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024
- Cataclysmic Variables: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024-01
Please subscribe to these threads if you are participating in the campaign so you can be updated, ask questions, and join in the discussion!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ
Alert Notice 845 reports on the HST observing schedule for ASASSN-18dg. Please see the notice for details and observing instructions.
There are threads for this campaign under the following AAVSO forums:
- Campaigns and Observing Reports: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024
- Cataclysmic Variables: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024-01
Please subscribe to these threads if you are participating in the campaign so you can be updated, ask questions, and join in the discussion!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ
Link to the Alert Notice has been corrected - apologies! - Elizabeth
Alert Notice 848 announces the scheduling with HST of the CV SDSS J080449.49+161624.8 (Cnc). Please see the notice for details and observing instructions.
There are threads for this campaign under the following AAVSO forums:
- Campaigns and Observing Reports: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024
- Cataclysmic Variables: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024-01
Please subscribe to these threads if you are participating in the campaign so you can be updated, ask questions, and join in the discussion!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ
Hi I have a few questions. First, in trying to properly identifying the target, I see that charts for this star, of varying fields of view (e.g., X35870AKU that I ran) show a dim unlabelled star at just next to the left crosshair. The deepest images I can generate have no such star, only the apparent target, which matches what I see in the SDSS (DR16) image of this field. What I am wondering is does that star exist, or is it really the target(!?).
I tried to share the SDSS image (color) and my CV image (mono, inverted)- didn't work. Please let me know if there is a more preferred way to share images.
The second question is re filters. I'm relatively new at this but have submitted data for the AB Aur campaign (B, V, R and HA). There, we do H-alpha photometry by measuring with R comp magnitudes, because no transforms exist. For this object, my SNR for V is poor (under 10 with 1 hr accumulated, I have only an 11" scope) but for CV/clear, I can get to SNR of about 18 with one hour of exposures (30x2 minute subs). I can't get Vphot to assign magnitudes if I upload as "CV." But if I upload the image as "V" it will assign a magnitude - is this what is meant by "reduced to V sequence"?
Third, the observing campaign provides r magnitudes for this star. I know you are asking for V, or even B, but is R useful? I can image deeper in R. Or perhaps I should opt for a target in the campaign list that is brighter(!).
Thanks!
Jeff
Hi Jeff,
This is a faint target (V~18.5) and it can be challenging indeed. In the SDSS images:
https://skyserver.sdss.org/dr18/VisualTools/explore/summary?ra=08%2004%2049.49&dec=16%2016%2024.8
https://skyserver.sdss.org/dr17/VisualTools/navi?ra=121.20628&dec=16.273483&scale=0.2
or the PanSTARRS image:
https://ps1images.stsci.edu/cgi-bin/ps1cutouts?pos=08+04+49.49+%2B16+16+24.8&filter=color&filter=g&filetypes=stack&auxiliary=data&size=350&output_size=0&verbose=0&autoscale=99.500000&catlist=
I don't see any other source nearby. The closest objects is ~14 arcsec north of the HST target. Maybe could you contact me privately to share your images so we can have a look at them together?
Regarding the filters, CV would be perfect for us if V is not feasible for you. We use V and CV to estimate the emission in the ultraviolet, which is finally used by the HST team to decide whether the target is safe of not for the COS detectors. Unfortunately R is not as useful since it covers a portion of the spectrum where the disc and the donor star start to contribute more than the white dwarf to the overall emission of the system, so the estimate in the ultraviolet becomes less reliable with R photometry.
About Vphot, I'm afraid I'm not be able to help since I'm not an user, but hopefully some other astronomers can give you some help/instruction on how the upload for CV works :)
I hope this helps!
Let me know in case you have more doubts or questions.
Best,
Anna
Hi Jeff,
This is a faint target (V~18.5) and it can be challenging indeed. In the SDSS images:
https://skyserver.sdss.org/dr18/VisualTools/explore/summary?ra=08%2004%2049.49&dec=16%2016%2024.8
https://skyserver.sdss.org/dr17/VisualTools/navi?ra=121.20628&dec=16.273483&scale=0.2
or the PanSTARRS image:
https://ps1images.stsci.edu/cgi-bin/ps1cutouts?pos=08+04+49.49+%2B16+16+24.8&filter=color&filter=g&filetypes=stack&auxiliary=data&size=350&output_size=0&verbose=0&autoscale=99.500000&catlist=
I don't see any other source nearby. The closest objects is ~14 arcsec north of the HST target. Maybe could you contact me privately to share your images so we can have a look at them together?
Regarding the filters, CV would be perfect for us if V is not feasible for you. We use V and CV to estimate the emission in the ultraviolet, which is finally used by the HST team to decide whether the target is safe of not for the COS detectors. Unfortunately R is not as useful since it covers a portion of the spectrum where the disc and the donor star start to contribute more than the white dwarf to the overall emission of the system, so the estimate in the ultraviolet becomes less reliable with R photometry.
About Vphot, I'm afraid I'm not able to help since I'm not an user, but hopefully some other astronomers can give you some help/instruction on how the upload for CV works :)
I hope this helps!
Let me know in case you have more doubts or questions.
Best,
Anna
Hi Anna
Thanks for your reply. Yes, the SDSS and PanSTARRS images are exactly what I am seeing!
Based on your replies, I am confident I am imaging (and measuring) the correct object. From your feedback and the survey images, the very faint star that is not in the crosshairs clearly is the target star! I must conclude that the AAVSO chart has a slight position error. I'll send you an image of the chart that has this star next to the crosshairs, but I'll work with AAVSO to figure out how it comes out that way.
No matter - I know what I am measuring is correct. The spectrum of this (very blue) star on the SDSS site is fascinating - it must be really hot! And of course is brightest in u and goes down through griz.
As for CV, I found a good link from MZK (Kenneth Menzies) who is a prolific contributor, and his instructions make sense. I have to adjust my FITS header a bit to have the photometry come out right. I think I am sorted there, so thanks. This also motivates me to finish my 14" Newtonian project(!) and get it on my observatory mount!
Kind regards,
Jeff
I'd be happy to share my most recent image of the target but don't want to be intrusive - if you wish you can reach me at jeffrey.n.myers@gmail.com
Dear All,
The time of the HST observations of SDSS J080449.49+161624.8 is the following:
Feb 16, 2024 23:31:31 - Feb 17, 2024 02:02:55 (UT time)
Any data you can collect on the next nights, especially the night of the 15th and early on the 16th, will be extremely useful for the HST team to finally approve the observations of this target.
Thank and all the best,
Anna
Alert Notice 850 announces the exact HST observing schedule on 2024 February 16-17 for the cataclysmic variable SDSS J080449.49+161624.8. Please see the notice for details and observing instructions.
There are threads for this campaign under the following AAVSO forums:
- Campaigns and Observing Reports: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024
- Cataclysmic Variables: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024-01
Please subscribe to these threads if you are participating in the campaign so you can be updated, ask questions, and join in the discussion!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ
Did the 16-17 Feb 2024 HST obs. take place?
Jim (DEY)
Dear All,
Sorry for the long silence. The observations of SDSS J080449.49+161624.8 were successfully executed in February. Thanks a lot for all your data!
Instead, the observations for ASASSN-20pv, which were originally planned to happened in March, have been postponed to the end of May.
The target for April, SDSS-J080846.19+313106.0 has been scheduled for next week, as follows:
Apr 5, 2024 22:41:47 Apr 6, 2024 04:23:03 - UT time
Any data you can collect on the next nights, especially the night of the 4th and early on the 5h, will be extremely useful for the HST team to finally approve the observations of this target.
In the meanwhile, for those celebrating, I wish you a very happy holidays!
Thanks and all the best,
Anna
Greetings,
The forecast weather at my observing site is grim at best over the next week, possibly the weather will allow something on the night of the 4th/5th but I wouldn't get my hopes up too high!
Others need to pick this object up, please. Currently SDSS-J080846.19+313106.0 is near 18.5 CV.
Jim (DEY)
Dear All,
This was a difficult target and the weather didn't cooperate on many sites, nonetheless your data were helpful to show that the target is in quiescence. The HST team has cleared the observations, which will happen tonight, as originally planned.
Thanks for all your work!
All the best,
Anna
Alert Notice 857 announces the scheduling with HST for April 5-6 of the CV SDSS J080846.19+313106.0 (Cnc). Please see the notice for details and observing instructions.
There are threads for this campaign under the following AAVSO forums:
- Campaigns and Observing Reports: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024
- Cataclysmic Variables: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024-01
Please subscribe to these threads if you are participating in the campaign so you can be updated, ask questions, and join in the discussion!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ
Alert Notice 860 announces that the cataclysmic variable ASASSN-19ct (Cen) will be observed with HST on 2024 May 17. Please see the notice for details and observing instructions.
There are threads for this campaign under the following AAVSO forums:
- Campaigns and Observing Reports: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024
- Cataclysmic Variables: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024-01
Please subscribe to these threads if you are participating in the campaign so you can be updated, ask questions, and join in the discussion!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ
Alert Notice 861 announces that the cataclysmic variable ASASSN-20pv (Vel) will be observed with HST on 2024 May 30. Please see the notice for details and observing instructions.
ASASSN-20pv is the second of two targets scheduled to be observed with HST in May for this campaign. The requested coverage intervals for both targets overlap, but if your observing time is limited, please give priority to covering ASASSN-19ct (scheduled for May 17 with HST, Alert Notice 860), then pick up ASASSN-20pv on the 17th.
There are threads for this campaign under the following AAVSO forums:
- Campaigns and Observing Reports: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024
- Cataclysmic Variables: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024-01
Please subscribe to these threads if you are participating in the campaign so you can be updated, ask questions, and join in the discussion!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ
Alert Notice 862 announces the exact times for HST observations of the cataclysmic variable ASASSN-19ct (Cen) on 2024 May 18 (date revised from Alert Notice 860). Please see Alert Notice 862 for details and observing instructions.
There are threads for this campaign under the following AAVSO forums:
- Campaigns and Observing Reports: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024
- Cataclysmic Variables: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024-01
Please subscribe to these threads if you are participating in the campaign so you can be updated, ask questions, and join in the discussion!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ
Alert Notice 863 announces the exact date/time for the HST observations of ASASSN-20pv: 2024 May 30 21:05:55 - May 31 00:18:45 UT
Observations in V tonight and tomorrow night are crucial. Please see the notice for details and observing instructions.
There are threads for this campaign under the following AAVSO forums:
- Campaigns and Observing Reports: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024
- Cataclysmic Variables: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024-01
Please subscribe to these threads if you are participating in the campaign so you can be updated, ask questions, and join in the discussion!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ