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photometry

Exoplanets and the Search for Extraterrestrial Life

 Variable Stars and the Stories They Tell:  

Exoplanets and the Search for Extraterrestrial Life

by Dale Bryant   

Alert Notice 454: Monitoring of CH Cyg requested for Chandra and HST observations

March 2, 2012:  Dr. Margarita Karovska, Harvard-Smithsonian Center for Astrophysics, has requested visual and photometric observations of the symbiotic variable CH Cyg in preparation for and support of Chandra and HST observations scheduled for later in March 2012. Dr. Karovska's observations will be a followup investigation of the central region of CH Cyg and its jet that was discovered a couple of years ago. AAVSO observations are requested in order to monitor the state of the system and correlate with the satellite observations.

Special Notice #265: Bright Symbiotics in Sgr, Cyg, and Oph

March 3, 2012: Observer S. O'Connor reported late last week that the symbiotic stars V4018 Sgr, CH Cyg, and V2523 Oph all appeared to be in outburst or brighter than normal.  He reports: V4018 Sgr at V=11.59 on JD 2455981.021 (2012 Feb 23.521); CH Cyg at V=7.30 on 2455982.976 (Feb 25.476); and V2523 Oph at V=11.67 on 2455981.0 (Feb 23.5).  Other more recent visual observations of CH Cyg by G. Holmberg (vis=7.6 on 2455983.4993) and D. Barrett (vis=7.4 on 2455985.6013) confirm the star is well above magnitude 8.0 at this time.

Filters

Approximate wavelengths for filters accepted for the AAVSO International Database

The filters listed below are used in the AAVSO International Database. For your reference, the approximate effective wavelength is given as well as the Full Width Half Maximum. These filters may be used when submitting observations to the AAVSO via WebObs.

Charts and Sequences Update November 2011

 Dear AAVSO Observers,

The following charts and sequences have been revised since the last update September 29, 2011. This batch of updates includes many stars from the YSO Section Observing Program, as well as stars visible only from the southern hemisphere.

There are also several updated sequences for HMXBs and WR stars from Gordon Sarty's HMXB Campaign.

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