The IAU accepts new members only every 3 years.
Membership applications are taken care of by the Canadian Astronomical Society Board, which is also the National Committee for Astronomy (NCA) for the IAU.
To apply for IAU membership, one must also be a CASCA member.
Information about who can apply and how to apply is available in the message that was sent to CASCA members.
The IAU membership form is available in Word and PDF formats.
The deadline to apply is November 1st, 2011.
Email questions to the CASCA Secretary: CASCA-Secretary -=at=- astro.queensu.ca