The AAVSO International Database has over 14.5 million variable star brightness estimates going back over ninety years. It is the largest and most comprehensive digital variable star database in the world. Over 400,000 new variable star brightness measurements are added to the database every year by over 700 observers from all over the world.

Quality

The AAVSO International Database is not only the largest but also the highest quality database available to researchers. The AAVSO and its technical staff spend more time and resources on database maintenance and quality control than any other organization.

Quality control begins before the observation is even made.
Extensive training materials are sent to new AAVSO observers and a large section of the AAVSO web site is designed specifically for observing techniques. The AAVSO holds two meetings per year where members come together to discuss their observing strategies, compare results, and much more. Workshops are routinely held at these meetings bringing the best professionals in the field in contact with the observers. Since 2000, workshops have been held on CCD imaging, Eclipsing Binary star observing, GRB afterglow hunting, and data analysis. The AAVSO also has an active mentoring program for new observers.

The AAVSO has over 3,000 variable star charts and strongly recommends that observers submitting observations to the AAVSO use these charts for standardization and homogeneity of the AAVSO International Database.

We have data entry error checks at every stage in the process.
Whether the observer is using WebObs, PCObs, or sending their data in via e-mail, we have error checking routines running to automatically identify the most common data entry errors. In addition, every month we comb through all the observations using both human and automated programs to look for misidentifications, typos, and any other errors. The best check, however, is the observers themselves who check their submitted data by using the Quick Look file, Light Curve Generator, and by comparing their own records with the observer totals we send out via postal mail every year.

Data validation ensures the quality of our permanent archives.
This practice is what really separates AAVSO data from others. Every data point that comes from the AAVSO International Database has been validated, i.e. put through a rigorous system of data integrity checks. This system involves running automated programs and also requires a human being to actually look at and validate each datapoint. Not a point gets through the system without being looked at by a real person. This combination of techniques takes advantage of the benefits both humans and automation can bring to the process, and it is applied not only to new observations, but to every observation in the database, even the ones made a century ago.

Observers

The AAVSO International Database would not exist without the dedication, tireless effort, and enthusiasm of thousands of variable star observers. Our observers come from all over the world. As of 2003, over 2/3 of AAVSO observers contributing data annually come from outside of the United States. Thanks to this broad network of observers we have coverage across most time zones and latitudes regardless of weather or other regional disruptions. To make it easier for the widely-scattered AAVSO members/observers to gather together in person, the AAVSO meeting(s) held every spring or summer take place in different parts of the United States or, as often as possible, in different countries.

The AAVSO receives observations from members of other variable star observing associations around the world for inclusion in the AAVSO International Database and dissemination to the astronomical community worldwide. These observations are sent regularly by the group leader/representative or directly by the group members themselves. The AAVSO values highly these fruitful, mutually beneficial collaborations, and truly appreciates the ongoing efforts of everyone involved in working together for the benefit of the astronomical community.

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