variable stars

Special Notice #222: Bright Supernova in UGC 5189A: SN 2010jl

November 5, 2010: We have been informed by Tim Puckett and by the Central Bureau for Astronomical Telegrams (CBET 2532, Daniel W. E. Green, Ed.) of the discovery of a bright possible supernova in UGC 5189A by J. Newton and Puckett, Portal, AZ, on November 3.52 UT at unfiltered magnitude 13.5. Confirming images (limiting magnitude 19.1) by Puckett on Nov. 4.50 UT showed the object at magnitude 12.9./p>

Special Notice #221: Infrequent Outburst of the SU UMa Variable HT Cas

November 2, 2010: As reported by Tim Parson (Circle Pines, Minnesota, USA) and confirmed by Pavol Dubovsky (Kolonica, Slovakia), the infrequently-outbursting dwarf nova HT Cas is in outburst.  Parson observed HT Cas in outburst at m(vis)=12.9 on JD 2455502.93 (2010 November 2.43), and the outburst was confirmed by Dubovsky at m(vis)=12.4 on JD 2455503.3 (2010 November 2.8).  The last confirmed well-observed outburst of this star occurred on 2008 January 10.  Observations of this variable are strongly encouraged at this time.  Both visual and CCD observations are en

Variable star posters and talks

AAVSO staff members frequently give talks and present posters on the AAVSO, its activities and its mission.  The list of presentations below is a partial compilation of talks and papers given by AAVSO staff over the past several years.

The work of many lives: four centuries of light curves (and counting) (1.9MB PDF), M. Templeton, Stars: Old, Young, and Variable, Iowa State University, May 2014

The Cosmic Distance Ladder

Distances in the universe are so vast that we do not have a simple way of measuring them.  For distances within the solar system we can measure them directly, using radar for example, and some very straightforward trigonometry.  But radar is hard to use when it takes light minutes or hours to cross the solar system; and the nearest star is four light years awa

Naming Variables

The International Astronomical Union (I.A.U.) appoints a committee that determines the names given to variable stars. The assignments are made in the order in which the variable stars were discovered in a constellation. If one of the stars already having a Greek letter name is found to be variable, the star will be referred to by the Greek name.