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AAVSO Alert Notice Archive

This AAVSO Alert Notice Archive page is obsolete as of July 31, 2017. For the current version of this page, please go to


This page contains links to past AAVSO Alert Notices, ordered by issue number with most recent issues first.  AAVSO Alert Notices are issued irregularly when researchers request critical supporting observations, or we have been notified of highly significant events.

Alert Notice 422: Observing Campaign on Hubble's First Variable in M31: M31_V1

July 16, 2010: An observing campaign is being carried out on M31_V1, the first variable star discovered in M31 by Edwin Hubble. The Hubble Heritage Team, with Dr. Keith Noll, Space Telescope Science Institute (STScI), as Principal Investigator, plans to observe M31_V1 with the Hubble Space Telescope (HST), and needs to know the phase of this Cepheid variable. Although basic parameters are known for this star, no recent photometry exists, so observations are required to generate current phase information.


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