As usual, the AAVSO Sequence Team has been working hard updating and improving charts and comparison star sequences. The following is a list of updates made during the first six months of 2019. If you observe any of these objects please update your charts and photometry tables with the most recent version as soon as possible. This list is also available for download in XLSX and PDF format (see the links at the bottom of this page.)
Updated May 24, 2019: Dr. Paula Szkody informs us that the exact time for the HST observation of V386 Ser has been scheduled for 2019 May 30 04:36-10:15 UT. This is the night of May 29/30 for US observers. Thus, the critical night will be May 28/29 (Wednesday night) to get a measurement to HST so they can proceed to the observation. It will be essential to have positive observations from this night to satisfy the HST planners, so observers with suitable equipment are urged to obtain positive measurements of this faint star.
May 14, 2019: Dr. Mark Kennedy (Jodrell Bank Centre for Astrophysics, University of Manchester) is urgently requesting observations of the potential cataclysmic variable CRTS J105122.8+672528 beginning immediately. This object appears to be in outburst, having brightened to V~16.2 from its minimum magnitude of V~18.5-CV~19.
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Note: R Aqr is out of its seasonal gap and is increasingly observable. Continued coverage is requested as described below until further notice. - Elizabeth O. Waagen, May 3, 2019
April 19, 2019: Dr. Lee Anne Willson (Iowa State University) is urgently requesting observations of the symbiotic Mira R Aqr, particularly from our Southern observers.
April 3, 2019: Dr. Bradley E. Schaefer (Louisiana State University) provides the following information:
"Frequent monitoring is requested of the recurrent nova U Scorpii over the next year or so to discover the upcoming very-fast eruption. The predicted outburst is for the year 2020.0±0.7. The eruption is likely within the next year, but it could well go off tonight.
"Observers of many types are needed before the next outburst:
