This stream appears to have been discovered during 1957 and 1958, while
radio-echo surveys were being conducted at Adelaide Observatory in South
Australia. A. A. Weiss reported the shower to have suddenly appeared with rates
of 30 per hour from a compact radiant. The radiant's position was determined as
RA=307 deg, DECL=-35 deg in 1957, and RA=301 deg, DECL=-36 deg in 1958. Weiss
said no hint of the shower had been noted in 1952, 1953, 1954 and 1956, and that
the 1957-1958 appearance was near "the limit of resolution of the equipment."
The date of maximum was given as June 11, while the total duration was given as
More sensitive radar equipment was operated by G. Gartrell and W. G. Elford
at Adelaide, South Australia, during 1968-1969. Only 4 meteors were detected, so
that the stream seemed practically nonexistent. For the mean activity date of
June 10, the radiant was established as RA=297 deg, DECL=-34 deg.
Visual activity from this shower seems rare, as some of the most
comprehensive southern hemisphere radiant catalogs (i.e. M1935 and Cuno
Hoffmiester's "Meteorstrome" in 1948) have failed to reveal convincing evidence
of the radiant's existence prior to 1957. Recent observations also appear to be
rare, although Jeff Wood, director of the meteor section of the National
Association of Planetary Observers (Australia), lists what appears to be a
probable detection of this shower among the 1980 observations of the Western
Australia Meteor Section. The radiant was called the "Alpha Microscopiids" and
was detected only during June 11 and 12. A maximum ZHR of 1.43±0.13 occurred on
June 11 from a radiant of RA=305 deg, DECL=-36 deg. The BMS Radiant Catalogue
lists this shower as occurring during June 8-16, with a maximum ZHR of 4, and an
average radiant of RA=304 deg, DECL=-35 deg.