May Librids

Observing

This stream possesses a very short duration extending from May 1 to 9. At maximum around May 6, the radiant is at RA=233 deg, DECL=-18 deg. The ZHR lies between 2 and 6.

History

This shower seems to have first been noticed on May 5, 1929, by three Texas members of the American Meteor Society. Oscar E. Monnig and Robert Brown were the first to detect the radiant. Monnig plotted 3 meteors from RA=230 deg, DECL=-16 deg, while Brown plotted 2 meteors from RA=229 deg, DECL=-16 deg. The mean time of both observations was given as May 5.32, and the radiants were given a poor rating of reliability. The third Texas observer was Blakeney Sanders. He plotted 3 meteors from RA=234 deg, DECL=-18 deg, at a mean time of May 5.35. The radiant was also considered to be of poor reliability.

The year of 1933 brought three more observations of this shower---this time from observers in Germany. The first was made by N. Richter on May 2, when his meteor plots revealed a radiant at RA=231 deg, DECL=-20 deg. Just 24 hours later, Cuno Hoffmeister observed a radiant at RA=235 deg, DECL=-19 deg. Finally, on May 6, Richter observed a radiant at RA=226 deg, DECL=-16 deg.

In Ronald A. McIntosh's 1935 paper entitled "An Index to Southern Meteor Showers," two radiants were recognized which might offer further observations of this shower. Radiant number 132 was called the "Gamma Librids" and was based on two previously observed radiants. The duration was given as May 9-11, while the average radiant was RA=232 deg, DECL=-15 deg. Radiant number 133 was called the "42 Librids." Its duration was May 3-9, while the average radiant was given as RA=233 deg, DECL=-23.5 deg. This shower was based on three previously observed radiants.

In the three decades following the 1930's, only three indications of this shower's existence appear in various publications. Paul Anderson (Beechwood, Michigan) plotted four meteors from RA=233 deg, DECL=-18 deg on May 7.24, 1942. The cameras of the Harvard Meteor Project photographed a magnitude 0.1 meteor on May 1, 1954, which possessed a radiant of RA=230 deg, DECL=-19 deg. The 1961-1965 session of the Radio Meteor Project detected several meteors from this stream during May 3-7. Zdenek Sekanina, director of the project, determined the date of nodal passage as May 5.8 (λ=44.8 deg), while the radiant was given as RA=233.0 deg, DECL=-19.5 deg.

The dearth of visual observations of this shower has changed in the last two decades as two well-organised groups of amateur astronomers in the Southern Hemisphere have begun systematic observations. J. E. Morgan, director of the Royal Astronomical Society's New Zealand meteor section, compiled a list of the active showers observed by his group during the 1970's. One radiant, designated as number 126, was called the "Lambda Librids" and was observed during May 4-15. The average radiant was given as RA=236 deg, DECL=-19.5 deg, while the maximum observed ZHR was 6. In Western Australia, Jeff Wood heads the meteor section of the National Association of Planetary Observers. During 1979, his group observed a radiant they called the "K Librids." Meteors were detected during May 5-6, with a maximum ZHR of 3.30+/-0.72 coming on May 5, from RA=233 deg, DECL=-19 deg. During 1980, Wood's group observed a radiant referred to as the "Iota Librids." Activity was detected during May 3-4, with a maximum ZHR of 2.15+/-0.10 coming on May 3 from RA=232 deg, DECL=-20 deg.