Introduction to Bulletin 73
Predicted dates for 2010 of maxima and minima of 562 long period and semiregular variables are given in this Bulletin. These dates have been determined using the AAVSO mean curves. As a convenience to the observer, approximate dates of maxima and minima for January and February of 2011 are also given. These dates are preliminary and are subject to change when the official predictions for 2011 are published. This Bulletin may also be found on the AAVSO web site page http://www.aavso.org/publications/bulletin .
An asterisk (*) preceding the designation indicates a star does not have a mean curve, thus predictions of their maxima and minima are questioned. Also questioned are maxima and minima of those stars not behaving predictably.
RANGE VALUES ARE ALL VISUAL. Range values given within the symbols "< >" are average maximum and minimum visual magnitudes and are taken from the third edition of the General Catalogue of Variable Stars and its Supplements. Range values given without "< >" symbols are mean visual magnitudes of the brightest maximum and faintest minimum obtained from the data in the AAVSO International Database since 1961. The values of maximum and minimum for an individual cycle may be much brighter or fainter than the range values given in the Bulletin.
In the monthly grids, the letter "M" indicates a predicted maximum; the letter "m" indicates a predicted minimum. The number preceding the letter "M" or "m" indicates the predicted date of maximum or minimum for each star. The "+" symbols on either side of the "M" or "m" show the estimated intervals during which the star will be brighter than visual magnitude 11.0, according to information supplied in AAVSO Bulletin 27. Also, the "-" symbols on either side of the "m" show the estimated interval during which the star will be fainter than visual magnitude 13.5, again according to AAVSO Bulletin 27.
My sincere thanks go to Katherine L. Davis, who wrote software to allow the fitting of mean curves on-screen and automatic digitization of extrema dates for all Bulletin stars, and who placed the Bulletin on the AAVSO website. I also thank Matthew R. Templeton for helpful discussions, and Charles M. Jones and Grant Foster, who wrote the software to produce the Bulletin itself.
The observations for this Bulletin are the contributions of AAVSO members and observers in the United States and abroad. Contributions have also been made by members of the following Variable Star Associations: Agrupacion Astronomica de Sabadell (Spain); Asociacion de Variabilistas de Espagne (Spain); Asociacion Argentina Amigos de la Astronomia; Association Française des Observateurs d'Étoiles Variables (France); Association of Variable Star Observers “Pleione” (Russia); Astronomical Society of South Australia; Astronomical Society of Southern Africa, Variable Star Section; Astronomischer Jugendclub (Austria); Astronomisk Selskab (Scandinavia); Brazilian Observational Network REA; British Astronomical Association, Variable Star Section (England); Bundesdeutsche Arbeitsgemeinschaft für Veränderliche Sterne e.V. (BAV) (Germany); Israeli Astronomical Association, Variable Star Section; Koninklijke Nederlandse Vereniging Voor Weeren Sterrenkunde, Werkgroep Veranderlijke Sterren (Netherlands); Liga Ibero-Americana de Astronomia (South America); Madrid Astronomical Association M1 (Spain); Magyar Csillagászati Egyesület, Változócsillag Szakcsoport (Hungary); Norsk Astronomisk Selskap, Variable Stjernegruppen (Norway); Planetario e Observatorio Astronomico do Colegio Estadual do Parana (Brazil); Red de Observatores de Estrellas Variables - MIRA (Spain); Royal Astronomical Society of Canada; Royal Astronomical Society of New Zealand, Variable Star Section; Ukraine Astronomical Group, Variable Star Section; Uniao Brasileira de Astronomia, Variable Star Commission (Brazil); Unione Astrofili Italiani (Italy); URSA Astronomical Association, Variable Star Section (Finland); Variable Star Observers League in Japan; Vereniging Voor Sterrenkunde, Werkgroep Veranderlijke Sterren (Belgium).
We gratefully acknowledge the astronomical contribution of each observer.