Special Notice #267: HST observations of CH Cyg scheduled and monitoring urgently needed

March 15, 2012:  As announced in AAVSO Alert Notice 454 (http://www.aavso.org/aavso-alert-notice-454), Dr. Margarita Karovska, Harvard-Smithsonian Center for Astrophysics, has requested multiband photometry (all possible bands), high-speed photometry, spectroscopy, and visual observations of the symbiotic variable CH Cyg in support of HST and Chandra observations. She is studying the central region of CH Cyg and its jet.

Dr. Karovska informs us that the HST observations of CH Cyg have been scheduled for 2012 March 18 01:55:22 UT - 05:48:24 UT.

The Chandra observations will be also made some time late this week and during next week. The Chandra schedule has been affected by the large solar flare experienced last week.

Please continue to observe CH Cyg during this and the next few weeks - at least through the end of March - to provide solid optical data crucial to interpreting the satellite data. With the high-speed photometry, a cadence of as low as a few seconds would be ideal, but a cadence of about a minute may also be all right to reveal high-speed variations. CH Cyg is currently at magnitude V=7.1, according to observations in the AAVSO International Database.

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 (VSX) at http://www.aavso.org/vsx.

Please report all observations to the AAVSO International Database as CH CYG.

Thank you for your astronomical efforts and valuable contributions!

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

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