SS Cyg campaign - Alert Notice 720

American Association of Variable Star Observers (AAVSO)
Sun, 09/13/2020 - 23:48

AAVSO Alert Notice 720 announces an observing campaign on the cataclysmic variable SS Cyg. Please see the notice for details and observing instructions.

To stay informed about this campaign, particularly about the date of its ending, subscribe to this forum thread (option 1 under Subscribe below) -  see feedback from the PI,  comments and questions from observers, and notes from AAVSO HQ. Add a post yourself  -  join in the discussion about this interesting target!

Many thanks, and Good observing,

Elizabeth O. Waagen, AAVSO HQ

American Association of Variable Star Observers (AAVSO)
SS Cyg with the Bright Star Monitors

This star is easy to do with the AAVSO's network of robotic telescopes, but no one at this time has submitted a proposal to monitor SS Cyg.  The network is available to all AAVSO members, so this might be an opportunity to try it out.  See

and note the "proposal section", giving you a link and information on how to fill out the form.


American Association of Variable Star Observers (AAVSO)
Rc Comp Star Magnitudes for SS Cyg

Dr. Mariko Kimura is asking for V and R band photometry of SS Cyg.  Finding the V band magnitudes for the comp stars is possible from the Field Photometry report of VSP.  But where does one look up the R band data for the comp stars? 


Donn Starkey

American Association of Variable Star Observers (AAVSO)
Request R mags when using VSP

Hi Donn,

When requesting a chart, check off the box for R at the very bottom of the chart request form. The R mags (as well as the V) will be shown in the photometry table of the chart that is created.

Good observing,


SS Cyg: the current state

Hi, I'm Mariko Kimura and the PI of this campaign.  

Thanks to the AAVSO and VSNET campaigns, I found that the X-ray irradiation of the secondary star may be weak by the Rc-band data.  However, I do not confirm this by the V-band data.  The data may be not enough or the orbital profile becomes complex for some reasons.  The X-ray flux is gradually increasing still now and I continue to perform multi-wavelength observations of this target.  The current mean V-band magnitude is ~10.8.



Bundesdeutsche Arbeitsgemeinschaft fur Veranderliche Sterne e.V.(Germany) (BAV)
Variation of V band data within few minutes

I just checked V band data for SS Cyg and see strong variations up to 0.6 within a very few minutes for some observers. Example: Data from last night from observer PSD show values between 10.4 and 10.9 within a period of only 7 minutes. But the incertainty for every data point is given below 0.05. This would mean that the variation has significance. Is this truly the case? 


I think those variations are

I think those variations are real.  I observed SS Cyg in the normal quiescent state in the past and similar variations were detected.  This behavior may be typical in U Gem-type dwarf novae.  These variations probably come from the bright spot at the outer disk rim or the visinity of the white dwarf.


Association Francaise des Observateurs d'Etoiles Variables (AFOEV)
Outburst started today

An outburst started today. 1.5 hours ago I saw SS Cygni at mag. 9.4.

Clear skies,

Royal Astronomical Society of Canada (RASC)
SS Cygni: in outburst

Just began a series of images for SS Cyg, which confirm a mag ~9.3.

Last night I spent more than 6 hours on it, just began reducing the images, Data will be uploaded in an hour or two.


SS Cyg in outburst

As you know, SS Cyg is now in outburst.  Maybe this time is not the case, but sometimes this source shows precursor outbursts.  The precursor outburst is always a long outburst.  The mechanism of this precursor is still unknown, so the observations at the rising part to the light maximum is important.  


American Association of Variable Star Observers (AAVSO)
Continue to image for the alert??

Should we keep imaging?  I have clear skies coming so can jump on this for a few hours this week before I start on V392 Per.

Observation plan

Sorry for my slow response.  I was checking the optical and X-ray recent activity of SS Cyg.  This source started fading at both wavelengths.  I don't know how this source behaves in near future, but I will continue monitoring until the X-ray flux returns back to the normal one and then stop observations.  Thanks a lot for your cooperation.  If the X-ray state has changed, I'll let you know.  


Observation plan 2

I'm so sorry for my slow response.  I felt very bad until the end of last year.  

I think SS Cyg keeps an anomalous state still now and last week the bright hard X-ray flare is detected by Swift/BAT (  The previous optical outburst did not decay completely and entered the next one.  I observed SS Cyg by some X-ray telescopes last weekend and am checking the data.  

This optical and other wavelengths behavior seems very interesting.  However, it is difficult to observe SS Cyg now because of a seasonal gap and I have already obtained a lot of data from the AAVSO community.  Thank you so much.  Also, I have to take maternity and childcare leaves since this May for ~1 year and I'm summarizing the data analyses by using AAVSO data.  Therefore I should stop my campaign.  If I notice other interesting features, I will announce them on this forum.  Thank you.  

American Association of Variable Star Observers (AAVSO)
Observation plan 3

I'm checking the curious behavior (the present standstill) of SS Cyg now.  

I'd like to extract orbital light curve at this standstill if possible.  I'm using Rc-band data to do this.  Also, B-V color is helpful to investigate what region is bright in the disk. Moreover, the monitoring by many color filters (U, B, V, Rc, Ic, and near-infrared bands) will be helpful in considering the disk temperature distribution.  
Therefore, I would like to request Rc-band time-resolved photometry and the daily monitoring by color filters in order to achieve my goal.  

Thanks a lot for your cooperation.

- Mariko Kimura

American Association of Variable Star Observers (AAVSO)
SS CYG current outburst

I'm doing photometry on SS CYG using BSM/NM2.  Current outburst duration is longer than past cycles... very interesting.