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    <Description xmlns="http://jabber.org/protocol/pubsub#event">
      Alert Notice from the AAVSO
    </Description>
    <Who xmlns="http://jabber.org/protocol/pubsub#event">
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      <Author>
        <shortName>
          AAVSO
        </shortName>
        <contactName>
          Richard C.S. Kinne
        </contactName>
        <contactEmail>
          rkinne at aavso.org
        </contactEmail>
      </Author>
      <Date>
        2011-08-19T20:08:47
      </Date>
    </Who>
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    <What xmlns="http://jabber.org/protocol/pubsub#event">
      <Param name="aavsoNumber" value="445" />
      <Param name="event" value="AAVSO Alert Notice 445: Request for monitoring of SS Cygni in support of European VLBI  radio observations" />
      <Param ucd="meta.link.url" name="link" value="http://www.aavso.org/aavso-alert-notice-445">
        <Description>
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        </Description>
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      <Param ucd="meta.id" name="objectName" value="SS Cyg">
        <Description>
          Standard name for the astronomical object
        </Description>
      </Param>
      <Param dataType="float" ucd="phot.mag" name="magnitude" value="11.0">
        <Description>
          Approximate magnitude of the object.
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          Following their very successful multiwavelength observing campaign 
on the dwarf nova SS Cygni in 2010 April (see AAVSO Special Notices 
#204 and 206 at http://www.aavso.org/special-notice-archive and the 
related information page at 
http://www.aavso.org/multiwavelength-observations-ss-cygni), 
Dr. James Miller-Jones (International Centre for Radio Astronomy 
Research, Curtin University, Perth, Western Australia) and colleagues 
have a follow-up multiwavelength campaign on SS Cyg scheduled. As 
before, they are requesting the assistance of AAVSO. 

THE FIRST POTENTIAL OBSERVATION DATE IS AUGUST 25-26, 2011.

Dr. Miller-Jones writes, ?To bring you up to speed with our main 
results, we found marginally-significant evidence for a resolved 
radio jet following the outburst, and the highly-accurate positional 
information we obtained from our VLBA campaign implied that the 
currently accepted distance and proper motion for the source 
(derived from HST observations) cannot both be correct, although 
we do not yet have sufficient radio data to determine the true 
parameters.  We therefore requested (and were awarded) follow-up 
observations with the European VLBI Network to rigorously 
constrain the distance and proper motion.  There is approximately 
one day per month when we will be able to trigger the EVN.  
These are:
-  2011 August 25-26
-  2011 September 6-7
-  2011 October 17-18
-  2011 November 23-24
-  2011 December 14-15

The possible trigger dates will continue through 2012, although 
the exact dates are not known yet for next year. Ideally we would 
like to know the state of SS Cyg (particularly whether or not it 
is going into outburst) a few days before each of these dates, to 
give us time to alert the schedulers and get on the telescope if 
appropriate. We would be extremely grateful for any assistance the 
AAVSO could provide.?

SS Cyg is the class prototype of the dwarf novae, and the brightest
dwarf nova in our skies. In quiescence, SS Cyg varies around V=12.0, 
and will typically reach V=8.0 at maximum, although anomalous weak 
outbursts are sometimes seen.  SS Cyg last went into outburst 2011 
June 26 (JD 2455738.75171, 11.49 V, R. James; 2455739.4201, 10.9, 
M. Bisson); the outburst was a wide one, lasting 20 days.  The next 
outburst may occur at any time.  Observations brighter than m(vis) 
= 11.0 should be reported as quickly as possible.

Observers are asked to increase their monitoring of SS Cyg at least 
through December.  Please report all observations as soon as is 
practical. In the event of an outburst, please report your 
observations as quickly as you can via WebObs, and also notify 
Dr. Matthew Templeton and Elizabeth Waagen at AAVSO Headquarters 
(matthewt@aavso.org, eowaagen@aavso.org).  Visual magnitude estimates 
are a fast and effective means of monitoring SS Cyg; CCD observations 
are also useful, but please reduce your frames and report your data 
as soon as possible following an observing run.  CCD time-series are 
not specifically required for this project.

Coordinates for SS Cyg: RA 21:42:42.79 Dec +43:35:09.9 (J2000.0)

Charts for SS Cyg may be plotted using AAVSO VSP:
http://www.aavso.org/vsp

This campaign is being followed on the AAVSO Observing Campaigns 
page at http://www.aavso.org/observing-campaigns

For more information on this project, please see Dr. Miller-Jones'
website: http://www.astro.virginia.edu/xrb_jets

Please promptly report all observations to the AAVSO International 
Database using the name &quot;SS CYG&quot;.

This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.
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                  2011-08-19T20:08:47
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              <Name2>
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                  325.67829166667
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