International Astronomical Union Circulars

Central Bureau for Astronomical Telegrams

The International Astronomical Union Circulars (IAUCs) are a series of postcard notices giving information about astronomical phenomena requiring prompt dissemination, particularly the discovery and follow-up of novae, supernovae and comets. The IAUCs are also available in electronic form via e-mail or through the CBAT/MPC Computer Service. [Note that the printed IAUCs are considered "official" and final; the e-mailed versions are officially issued but are not the final version, because they are issued in ASCII form (and do not entail diacritical marks, Greek letters, and other aspects). Official citing should always be to the printed IAUCs, not the electronic versions.]

On-line IAUCs are available. Please ensure that you have read this policy statement on the availability of IAUCs.


Sample IAUCs

Sample IAUCs are available showing a range of the material covered. The sample Circulars are available in two forms:

IMPORTANT NOTE: When looking at the sample IAUCs below, please note that the CBAT TWX number has been discontinued.

The available sample Circulars are:


Details on how to subscribe to the IAUCs are available.


CBAT