• WG Report 2021-2024: We are preparing a triennial WG report for 2021-2024 to the IAU Secretary. The WG members are kindly invited to submit the past year's reports to a.ivantsov (_at_) and massaf (_at_) before February 3, 2024. In case you have missed mentioning any related activities starting in 2021, please, feel free to mention them there, as well.

    Purpose of this working group

    This Working Group on Astrometry by Small Ground Based Telescopes is a Working Group of the IAU Division A on Fundamental Astronomy.

    It has been initiated during the XXVIth General Assembly of the IAU in Prague, in August 2006 by the Division 1 (Fundamental Astronomy) of the IAU. It has been extended by the division 1 or division A during the following general assemblies.

    The goal of this WG is to update and maintain information on astrometric programmes and activities carried out by small telescopes (up to 2m diameter), to diffuse news through these pages and by e-mails, to facilitate the collaborations and to help for the coordination of the activities, when possible, in astrometry from ground-based telescopes.

    These telescopes are generally easier to access than the larger ones and allow us to carry out observational programs on medium and long term. Thanks to these properties they are precious tools to contribute to the advance of our knowledge of the celestial bodies: many Solar System objects and some astrophysical objects. More generally, the small telescopes due to their number and their geographical spread, are very efficient for observation in network. This is a strength which is successfully applied for coordinated programs.

    The intent of the Working Group is to help coordinate the existing programmes, to exchange information at an international level and to encourage participation in different projects in astrometry at large. Astrometric measurements of positions for dynamics, fundamental astronomy or astrophysics, but also photometric observations of events for determination of size and shape, determination of the parameters of rotation can pay benefit from these instruments. This is possible for example thanks to observations of mutual events of the natural satellites, stellar occultations, mutual events of binary asteroids, etc. Several such campaigns are encouraged.

    Furthermore the role of the WG is also to teach the astrometry theory and practice to the next generation, this is why the organization of training stays are promoted.


    The Working Group operates mainly by e-mail. Follow this link for a list of the current Members of the Working Group. To the members: please send any updated email addresses or changes of Institutes to the IAU Secretariat at: iauinfos(at)

    How to join the Working Group?
    If you are interested in the WG activities and would like to contribute to them, we will be glad to get a message from you sent to a.ivantsov(_at_) and massaf(_at_)

    Astrometric activities


    In this section, we post a list of relevant documents and references related to astrometry by small ground-based telescopes. Don't hesitate to send such new references to the chairperson of this WG.


    The following links are related to the topics of the WG:

    Updated: 13 January 2024
    by William.Thuillot(at)