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Special Notice #320: CH Cygni monitoring campaign continues

January 9, 2013: Further to AAVSO Alert Notice 454 ( and AAVSO Special Notices #267, #268, and #294 (, -268, -294), Dr. Margarita Karovska (Harvard-Smithosonian Center for Astrophysics) has requested the continuation of multicolor coverage, particularly B and V photometry, as well as visual observations of the symbiotic variable CH Cyg.

The multicolor coverage through early December was excellent and very helpful, according to Dr. Karovska. "It will be very important (if possible) to contine the monitoring, especially because the last few months' cycle seem to be longer and a bit different...Also, this current campaign is the first time CH Cyg is being monitored in B for an extended period by the AAVSO."

Time series observations are not necessary; one or two observations per night will be sufficient. Visual observations
have been valuable throughout this campaign and visual observers are encouraged to continue their observations.

Please continue your observations of CH Cyg as best you can and report all observations to the AAVSO International Database as CH CYG.

Coordinates: RA 19 24 33.07  Dec. +50 14 29.1 (J2000.0)

Charts for CH Cyg may be plotted using the Variable Star Plotter (VSP) at

This campaign is being followed on the AAVSO Observing Campaigns page (

Thank you for your astronomical efforts and valuable contributions!

This AAVSO Special Notice was compiled by Elizabeth O. Waagen.


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