On-line IAUCs are generally available, though older IAUCs are still being scanned in gradually. Below are jpeg images of many of the older IAUCs published at the Royal Observatory of Uccle (where Nos. 1-31 of the first series were issued) and at the Copenhagen Observatory (where Nos. 1-1883 of the second series were issued), as well as some of those older IAUCs published in Cambridge (beginning in 1965). The 31 Circulars that were published by the IAU's Uccle office of the Central Bureau during 1920-1922 were printed on regular-sized paper. When the Elis Strömgren at the Copenhagen Observatory assumed publication of the IAUCs in 1922, they started over again at No. 1 and continued printing their circulars on cards for easier mailing. (The IAU was actually formed in 1919.) The postcard concept goes back to 1914, when Strömgren began issuing urgent astronomical information on postal cards because of disruptions incurred by the first world war that affected the CBAT at Kiel; when the IAU moved its CBAT to Strömgren's direction at Copenhagen in 1922, Strömgren naturally transformed his early postcard system into the new version of the IAUCs.
We have been assisted by other libraries (including especially the U.S. Naval Observatory Library in Washington, and the Copenhagen Observatory Library) in obtaining better copies of older IAUCs where the Harvard College Observatory (HCO) Library copy is inferior (by way of torn cards or text-imposing postage marks). The goal is to have most of the Copenhagen-issued IAUCs available here as jpeg images and all of the remaining IAUCs available here as plain-ASCII-text files, by the end of the year 2009. We thank Sally Bosken (USNO Librarian), her assistants, and Lone Gross (Astronomical Observatory Library, University of Copenhagen), for their time and effort in helping to augment the HCO/SAO collection of older IAUCs.
The CBAT began in Kiel, Germany, in 1882, where the world's most preeminent astronomical journal (Astronomische Nachrichten) was published (not a coincidence!). The A.N. was published approximately once a week for many years in the 19th century, and it was considered a primary source for announcing new discoveries of astronomical objects, but it was a journal format (and thus larger than the announcement bulletins and circulars that would follow in the 20th century). Telegrams were issued from Kiel (and HCO, and soon also Copenhagen), but these were generally coded to avoid mistakes (and thus not generally readable), and copies of old telegrams are exceedingly rare -- the printed versions being the sole surviving form of most older discoveries. The A.N. staff began its own version of the HCO Bulletins in 1919, which the Kiel editors named the Beobachtungs-Zirkulars. The B.Z. were typeset onto paper that was smaller than that of the parent A.N. publication, and it focussed on reports of new discoveries and follow-up information for such objects as minor planets, variable stars, novae, and comets. The B.Z., which was produced more irregularly than the A.N. (but which could be produced more quickly due to its smaller size), continued publication until 1944 (from Berlin), when the War forced a permanent end to its production.
Scans of "pre- and non-IAU/CBAT" postcard circulars that were published at Copenhagen beginning in 1914 are available here, as well. Another important task (with no time goal yet) will be to ensure that the HCO Announcement Cards and the HCO Bulletins are also available via the web; these HCO publications served as the mailed output from the western-hemisphere's version of the CBAT during 1895-1964 (with the HCO Circulars during 1895-1898), while western-hemisphere "central bureau" unprinted astronomical telegrams also were issued from HCO beginning in 1883 after transferral of this task was completed from the Smithsonian Institution in Washington, DC. The HCO Circulars were another related publication with more expanded information, and they have been scanned in and posted on the ADS website here (but note that they are merely Circulars with no volume numbers, despite what ADS says).
Various Older IAUCs
Various older IAUCs are available, with additional issues
posted here as time permits.
IMPORTANT NOTE: When looking at the IAUCs below, please note that the older postal and telegram addresses have been discontinued.
Series 1 (Uccle, 1920-1922)
Series 2 (Copenhagen/Cambridge, 1922-present)
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