Harvard College Observatory Circulars

The Harvard College Observatory Circulars (HCOCs) were begun in 1895 to announce information about astronomical phenomena requiring prompt dissemination. In 1898, the Harvard College Observatory Bulletins (HCOBs) replaced the HCOCs for rapid postal mailing of such astronomical news concerning new discoveries of comets, novae, etc., while the HCOCs continued for many years in expanded form. The HCOCs have been scanned in by the SAO's ADS service and are available at the ADS website here (but note that they are merely Circulars with no volume numbers, despite what ADS says).