------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 3141 2016 Feb 08 21.40UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074 INTERNET: GUY@TAHQ.DEMON.CO.UK Backup: gmh@wdcc1.bnsc.rl.ac.uk WORLD WIDE WEB http://www.theastronomer.org ------------------------------------------------------------------- SS CYGNI Dr. James Miller-Jones (International Centre for Radio Astronomy Research, Curtin University, Perth, Western Australia) and colleagues have requested assistance in support of their multiwavelength (radio and optical) campaign on the dwarf nova SS Cyg. Close monitoring of SS Cyg and immediate reporting of observations to the AAVSO via WebObs is requested beginning now. Dr. Miller-Jones writes: "Dr. James Miller-Jones and an international team are aiming to use the e-MERLIN array of radio telescopes (7 antennas spread across the UK) to observe the next outburst of the dwarf nova SS Cygni. They are aiming to determine whether or not resolved radio jets exist in this system, and will use the high angular resolution and exquisite sensitivity of e-MERLIN to make deep images of SS Cygni during outburst, when any jets, should they exist, would be most likely to be detectable. The outburst will also be tracked with dense monitoring from the Arcminute Microkelvin Imager - Large Array (AMI-LA; a radio telescope based in Cambridge, UK), to provide the most complete radio coverage of an outburst of any dwarf nova system to date. They seek support from the AAVSO both to trigger their radio observations, and also to provide optical coverage of the outburst that can be compared with their radio light curves." The radio emission in SS Cyg occurs early in the outburst, so it is essential to know when the outburst is beginning in order to trigger the multi-site radio observations. If the outburst cannot be detected early enough, the radio observations will not be triggered, but will be held for a later outburst. Data in the AAVSO International Database indicate that SS Cyg may go into outburst very soon, so please keep a very close watch. Visual and CCD/DSLR (particularly V) observations are requested (no time series unless outburst is underway and radio observations have been triggered). Its normal minimum magnitude is ~11.8 V, but it can fluctuate to around 11.5. If it becomes brighter than 11.5 V, it could well be going into outburst. If it reaches 11.0, it is almost certainly on its way up. Once SS Cyg goes into outburst, please continue your observations until SS Cyg has returned to minimum. The radio observations will continue throughout the outburst, so your optical data from the entire outburst will be essential for correlation. Coordinates: RA 21:42:42.8 Dec. +43:35:10 (2000.0) Editor: Please report to AAVSO but also include your results in the monthly TA report to Gary Poyner and in your BAAVSS database entries. Guy M Hurst