UK astronomers and space scientists are invited to help shape global policy and direction within the astronomy community by joining the International Astronomical Union (IAU) free of charge.
There is no cost to the individual for IAU membership because the fees are covered by the Royal Astronomical Society (RAS) and the Royal Society.
The UK was a founding national member of the IAU from its establishment in 1919, and the RAS is the UK adhering body. The IAU now has 85 member states, with an individual membership of more than 13,000 in 92 countries. It is the only global scientific union covering astronomy.
Its mission is to promote and safeguard the science of astronomy in all its aspects, including research, communication, education and development, through international cooperation.
Its individual Members — structured into Divisions, Commissions, and Working Groups — are professional astronomers from all over the world, at PhD level and beyond, who are active in professional research, education and outreach in astronomy.
The key activity of the IAU is the organisation of scientific meetings. Every year the Union sponsors nine international IAU Symposia. Every three years the IAU holds its General Assembly, which offers six Symposia, some 15 Focus Meetings, and individual business and scientific meetings of Divisions, Commissions, and Working Groups and Offices.
The Union also supports offices with responsibilities including young astronomers, education, outreach, and using astronomy for development, and the Minor Planet Centre. Since 2022 the IAU Centre for the Protection of the Dark and Quiet Sky has helped coordinate the global effort to mitigate the impact of satellites on astronomy.
One of the responsibilities of the RAS as the UK national representative is to publicise the annual call for new members from our astronomy community. If your application for membership is accepted, you will be able to help shape the policy and direction of the organisation and assist it to best represent the gamut of interests of the astronomical community.
We particularly encourage applications for IAU membership from women and other under-represented groups to ensure that the diversity of our community is properly served by the Union. We also invite RAS Fellows to apply if they are not already a member.
The IAU has two categories of membership: Individual and Junior. As a rule, Individual Membership in the IAU is open to scientists with a PhD or equivalent in a branch of astrophysics. Scientists who have completed their PhD studies between the years 2020 and 2025 are eligible candidates for Junior Membership.
There is now a single application form for both categories of membership. Before completing an application, check the IAU website to ensure you are eligible to apply. You will then need to create an account to access the application form.
Junior Members who joined the IAU in 2020 should now apply as Individual Members in this call. The IAU website can also create a list of members in the UK who may be able to act as suitable referees.
If you have any questions about the application form, please contact the IAU directly.
The deadline for applications is 31 December 2025.