Revised 2013 April 17
The AAVSO International Database is a collection of variable star observations made primarily by the amateur astronomical community, and includes data from AAVSO observers, observers affiliated with other variable star astronomy organizations that share and archive data with us, and data from professional researchers and published literature. Data are served in three primary ways: through the Light Curve Generator, via the QuickLook web tool, and via Data Download. In all cases these data are freely available to the community, but we request that users adhere to the policy outlined below. Doing so indicates that you support the mission of the AAVSO, and respect the organization and the worldwide community of observers who provided these data to you.
The AAVSO International Database is the product of the ongoing efforts and expertise of the volunteer observers who contribute the data and the AAVSO Headquarters technical staff who prepare and maintain the database with high quality-control standards. Please resepect their and our work by using these data in accordance with our policies.
Our policy for use and acknowledgement of the AAVSO and data from the International Database is as follows:
Please use the AAS facilities keyword  "AAVSO" in your AAS journal publications. This keyword was assigned by the American Astronomical Society and both raises the profile of the AAVSO observer community and helps us track data usage.
If AAVSO data are used for correlation with other types of data, such as multiwavelength observations, or as reference material, we request the following acknowledgement or one similar to it:
"We acknowledge with thanks the variable star observations from the AAVSO International Database contributed by observers worldwide and used in this research."
All observations include information about the affiliation of the observer (if different than the AAVSO) and we encourage you to include acknowledgement of those organizations as well.
When unpublished AAVSO data are specifically referred to in the text, they should be referenced in the following manner (using appropriate format):
Henden, A.A., 2013, Observations from the AAVSO International Database, http://www.aavso.org 
If one or more observers provide data that are critical to the outcome of your research, we strongly encourage you to offer co-authorship to those observers in papers resulting from that research. AAVSO staff will assist in making contact with those observers for this purpose if they choose to be included as co-authors.
The AAVSO no longer requests co-authorship for the Director or other AAVSO staff unless substantial staff assistance is required in the collection and analysis of AAVSO data. In this case, either the current director or the staff member responsible for the work will be designated for this role.
The AAVSO International Database is a precious resource for the science of variable star astronomy, and we hope your research will benefit greatly from the use of these data. The amateur and professional astronomers who have contributed data to the AAVSO over the last century did so hoping to make a positive contribution to variable star research, and it is our goal to facilitate the use of these data by the astronomical community. AAVSO data are and always will be provided free of charge upon request, as a service to the scientific community.
Our only requirements for the use of AAVSO data are simple:
First, please acknowledge the use of any and all AAVSO data used in publications with the appropriate acknowledgements we have provided above, and use the "AAVSO" facilities keyword in any AAS journal publications.
Second, if you use our data in a publication, please let us know ! We are thrilled to see the work of our observer community in print, and our observers are equally thrilled to see their work put to good use. The AAVSO has created the AAVSO In Print  page for just this purpose. It shows the observers that their work is paying off, it showcases your hard work in using and analyzing AAVSO data, and it proves to the astronomical research community that the AAVSO continues to be a relevant and valuable resource for variable star astronomy. If your paper is accepted, in press, or published in a magazine, journal, or conference proceedings, please email us at firstname.lastname@example.org  with the paper title, the authors, the year of publication, and the journal and reference information. If the paper appears on the arXiv.org preprint server, please include the URL for the abstract page.
Third, we encourage you to become members  of the AAVSO yourselves. For more than a Century the AAVSO has been a thriving community of amateur and professional astronomers involved in variable star astronomy, and we encourage all researchers making use of these data to become a part of the organization.
Finally, we encourage all grant-funded researchers to consider supporting the AAVSO under your current grants, adding the AAVSO as a partner in your next grant proposal, or supporting our mission with direct donations. AAVSO staff support both the observer community and the research community to provide these data, and financial contributions are gratefully accepted to make continued support possible.
We are very pleased to provide you with whatever data we have of interest to you. If our data prove valuable to your research, please let us know!
Dr. Arne A. Henden, Director
American Assocation of Variable Star Observers