The American Association of Variable Star Observers (AAVSO) and the British Astronomical Association Variable Star Section (BAAVSS) are pleased to announce that the variable star observation archive of the BAAVSS is now available through the website of the AAVSO. The BAAVSS archives comprise over 2.5 million variable star observations made mostly by amateur astronomers world-wide over the past 150 years. These data now join the archives of the AAVSO in the AAVSO International Database, which consists of over 25 million variable star observations made by observe
Use this form to access the American Relative Sunspot Number (Ra) as published by the National Geophysical Data Center (which is shut down pending a Federal budget agreement). These numbers reflect what was published by NGDC, and may contain typographical errors. For the official AAVSO value of Ra, see the AAVSO Solar Bulletin for specific month(s) you are interested in.
The AAVSO's volunteer-driven project to digitize paper archives of variable star observations is moving forward, and there have been some exciting developments over the past few months that deserve to be mentioned. Here, I'll summarize some of the happenings in this project, and talk about some of the issues that have arisen at AAVSO and among the volunteers.
Long-term observations of long period variable stars are essential to the determination of period, change in period, change in behavior resulting from mass loss and/or evolution, mode of pulsation (fundamental or overtone), internal structure, and phase at specific times for these stars.
A number of papers have been written discussing visual magnitude estimates in comparison to photometry. Multiple studies have shown that visual magnitude estimates compare very favorably with instrumental photometry in terms of sensitivity and consistency. As with all data, care must be taken to understand what visual magnitude estimates represent, what their bandpass is, and when their use is appropriate.
The AAVSO now distributes its published times-of-minimum data for eclipsing binary in single compressed files (.tgz and .zip), rather than as a searchable online index. For data on a specific star, unzip the compressed file, and search for the star's name among the included text files. These files contain updated publication information through November 30, 2005, the time at which the files were last updated.