Harvard College Observatory Announcement Cards
The Harvard College Observatory Announcement Cards (HACs)
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
took over the function of the
, which had been issued since 1898.) In 1964, it was
agreed by the International Astronomical Union that its
for Astronomical Telegrams
would move to
(and be operated by the Smithsonian Astrophysical Observatory staff
), and the
ceased publication at the
end of 1964, with its editorial staff converting to publish
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
, as well as interesting astronomical events such
as the discovery of Pluto. It is also planned to scan in
(and post here) most of
issued during World War II, when the issuance
suffered from communication problems due to
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.