Although visual observations of this shower seem virtually nonexistent, support for this stream appears in two radar studies conducted during the 1960's, as well as five photographic meteors detected over the period of 1937 to 1954.
The first official detection of this stream was made by B. L. Kashcheyev and V. N. Lebedinets (Kharkov Polytechnical Institute) during a radar survey conducted in 1960. The radar was not operated continuously, but five meteors from this stream were detected during March 14-15, from an average radiant of RA=172 deg, DEC=+3 deg. The stream was referred to as the "Sigma Leonids," and the orbit was given as
The stream was next detected by Zdenek Sekanina during the 1968-1969 session of the Radio Meteor Project. The data revealed a duration of February 13 to March 11. The nodal passage came on March 3.4 (solar longitude=342.3 deg), at which time the radiant position was given as RA=160.9 deg, DEC=+7.3 deg. The orbit is as follows:
The Author has examined the photographic data of the last few decades and has found five meteor orbits published by F. L. Whipple in 1954 and by R. E. McCrosky and A. Posen in 1961, which were detected between 1937 and 1954. The indicated duration was February 17-March 13, while the average radiant was RA=156.9°, DEC=+5.3°. The following orbit was determined.