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Special Notice #333: Eclipse underway in b Per and photometry needed urgently

February 6, 2013: According to photometry provided by Don Collins (CDK, Swannanoa, NC), the eclipse in the b Per system (HD 26961), predicted for around 2013 January 25, is underway now and began February 4-5. Photometry - multicolor if possible - is urgently needed now to cover the rest of this eclipse, which may last for up to four days altogether, and see post-eclipse behavior of the system.

The campaign to detect and monitor this eclipse in this bright (4.52 V) triple system is described in AAVSO Alert Notice 476 ( Dr. Bob Zavala (U.S. Naval Observatory, Flagstaff) requested AAVSO assistance in obtaining multicolor photometry in order to prepare for and detect a possible eclipse of the AB components by the C component. The eclipse is taking place about a week later than he had predicted it might occur.

Photometry is needed at the level of 0.02-0.03 magnitude or better. Instructions, comparison and check star identifications, etc., are given in Alert Notice 476.

Coordinates for b Per: R.A. 04 18 14.62  Dec. +50 17 43.8 (2000.0)

Charts may be created using the AAVSO Variable Star Plotter (VSP,

Observations should be submitted to the AAVSO International Database using WebObs or PEPObs and the name b PER.

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


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