The AAVSO Argelander Society

Named for Friedrich Argelander, who is considered to be “the father of variable star astronomy,” The Argelander Society offers membership benefits to individuals who have given a certain level of substantial financial support to the AAVSO over many years. Once a benefactor has donated a cumulative total of $35,000.00 to the AAVSO, they are eligible for a lifetime membership in the organization, free registration to Annual Meetings, invitations to special events, and other tokens of the association’s appreciation. 

Please consider donating today to the AAVSO, an international nonprofit organization, with a mission to enable anyone, anywhere, to participate in scientific discovery through variable star astronomy. You can give a general donation, which AAVSO uses where it is needed most, or you can choose your donation to be allocated to a specific fund.




Soon after Gary Walker became an Arglender Society member in 2015, Eduard Schoenfeld, another observer, had the chance to interview Gary and asked, "You've been a member for a long time. Has the change and growth of the AAVSO impacted your view of the importance of giving?" Gary answered,

"The Growth of the AAVSO has shown the need for giving. Most organizations can keep the status quo with their income, however just like in business, when you want to expand, outside capital makes things really move. You can't take it out of the profit, because there is usually not enough of it there.

"I have seen the AAVSO grow from all visual observations submitted on paper, to 100 CCD observations every six months to several hundred observations from dozens of observers each night. This has been aided by WebObs, charts, good sequences, lots of HQ support, and good fortune beyond anything we could have imagined in 1993, when I first became interested in CCD photometry. Many volunteers have contributed greatly, but the money to support HQ provides the glue, the continuity, and the vision to get things coordinate and done correctly. [F]unding AAVSO ensures that our mission will continue for another 100 years."

Argelander Society Members:

William B. Albrecht

Robert Martin Ayers

Marvin E. Baldwin

Richard L. Berry

John Centala

David H. Collins Estate

Gregory Conrad

Charles E. Curry

Margaret Doleman

Clinton B. Ford

Martha L. Hazen

Arne and Linda Henden

E. Dorrit Hoffleit

James Molnar

Gordon & Betty Moore Foundation

Gordon Myers

Richard S. Post

William Stein

David J. Sworin

Theodore H. N. Wales

Gary Walker

Thomas R. Williams


About Friedrich Argelander

Friedrich Argelander was the first astronomer to begin a careful study of variable stars. At the time, only a handful of variables were known, and he was responsible for introducing the modern system of naming them using the capital letters R-Z. It was believed that variability was a rare phenomenon and that this would provide plenty of names for the variables yet to be discovered. In a few years this proved inadequate and the naming system was extended to double letters, and then a numbering system. Today, tens of thousands of variable stars are cataloged, with more being discovered all the time.

The “Argelander Step Method” is a visual method of estimating the magnitude of a variable star. It involves comparing the variable with comparison stars of known constant magnitude, and assigning a step value that reflects the brightness of the variable as distinguished from that of the comparison star. The magnitude of the variable can then be calculated from the known magnitudes of the comparisons. This is very similar in practice to methods still used today by visual observers of variable stars.

Argelander is probably best known for the Bonner Dorchmusterung, the largest and most comprehensive of the pre-photographic star catalogs. He began mapping the exact positions of the stars in the northern sky in 1852, a monumental task before the use of photographic plates. When finally completed in 1863, it listed the positions of 324,198 stars down to ninth magnitude.