History
The primary sources for data supporting this stream’s existence come from R. A. McIntosh’s 1935 paper entitled “An Index to Southern Hemisphere Meteor Showers,” and the two sessions of Z. Sekanina’s Radio Meteor Project.
McIntosh listed two very similar radiants in his “Index.” The first was designated number 134 and was based on nine previously observed radiants. Its duration was given as April 13-21, during which time the radiant moved from RA=233.5 deg, DECL=-19 deg to RA=238.5 deg, DECL=-22 deg. The second radiant was designated number 141 and was based on three previously observed radiants. Given a duration of April 17-19, the average radiant was RA=236 deg, DECL=-15 deg.
Sekanina’s Radio Meteor Project revealed three radiants during the 1960’s. The 1961-1965 session revealed a stream Sekanina called the “Librids.” The duration was given as March 24-May 7, the date of the nodal passage was April 17.6 (Solar Longitude=27.2 deg), and the average radiant was given as RA=232.1 deg, DECL=-16.0 deg. Sekanina’s 1968-1969 session of the Radio Meteor Project revealed two fairly similar radiants in Libra. The first was called was called the “Librids” and was said to confirm the 1961-1965 stream. Its duration was March 10-April 21, the date of nodal passage was April 5.5 (Solar Longitude=15.2 deg), and the average radiant was RA=224.3 deg, DECL=-12.8 deg. The second stream detected in 1968-1969 was called the “Theta Librids.” Its duration was given as March 11-May 5, with the nodal passage occurring on April 18.4 (Solar Longitude=27.9 deg), and the average radiant being RA=236.3 deg, DECL=-18.4 deg.
The only additional visual radiant noted in the literature, aside from McIntosh’s, was detected by W. F. Denning during April 16-21, 1887, when five slow and long meteors were plotted coming from a radiant at RA=235 deg, DECL=-15 deg.