Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

Harvard College Observatory Announcement Cards

The Harvard College Observatory Announcement Cards (HACs) served during 1926-1964 to announce information about astronomical phenomena requiring prompt dissemination -- particularly the discovery and follow-up of novae, supernovae, and comets -- specifically for astronomers in the western hemisphere. (The HACs effectively took over the function of the HCO Bulletins, which had been issued since 1898.) In 1964, it was agreed by the International Astronomical Union that its Central Bureau for Astronomical Telegrams would move to HCO (and be operated by the Smithsonian Astrophysical Observatory staff there), and the HACs ceased publication at the end of 1964, with its editorial staff converting to publish the IAUCs instead. Below are some select HACs (in jpeg image form) provided to show interesting historical issues (including the beginning and ending of HCO's publication of the HACs, as well as interesting astronomical events such as the discovery of Pluto. It is also planned to scan in (and post here) most of the HACs issued during World War II, when the issuance of IAUCs suffered from communication problems due to the war.

Various HACs

Various HACs are available here, with additional issues posted here as time permits. HACs 44 and 45 deal with the bright, naked-eye daylight comet C/1927 X1 (Skjellerup-Maristany). The HACs below in the range 108-157 deal with the discovery and follow-up observations/calculations regarding Pluto. The bright nova DQ Her (which reached visual mag 1.5) appears on HACs 318-320. The bright comet C/1941 B2 (de Kock-Paraskevopoulos) appears on HACs 565-573. The bright nova CP Pup (which reached visual mag 0.5) appears on HACs 637-641. The bright "Southern comet" C/1947 X1 appears on HAC 863. The bright eclipse comet C/1948 V1 (old-style designations 1948l = 1948 XI) appears in the span HACs 952-960.

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