Alpha Lyrids

Observing

This is an apparently strong telescopic meteor shower with a duration extending from July 9-20. When at maximum on July 14 (λ=112°), the radiant is located at α=280°, δ=+38°. At the shower's discovery in 1958, activity rates in binoculars were estimated as 18-33 per hour. Naked-eye rates are about 1-2 per hour. The average magnitude of the meteors is 4.1 and their color appears to be primarily white. The meteors are also described as fast and seem to originate from a radiant 2° in diameter.

History

The Alpha Lyrids were discovered in July 1958, during a Czechoslovakian meteor expedition to Mount Bezovec. J. Grygar, L. Kohoutek, Z. Kviz, and J. Mikusek led the team of 44 observers from observatories and astronomy clubs. The purpose of the expedition was to obtain observations of sporadic telescopic meteors, but the observers ended up discovering a new meteor shower.

The Czechoslovakian observers watched the skies between July 10 and 25, but the Alpha Lyrids were only detected during July 10 to 20. Observations made with 25x100 binoculars revealed a maximum hourly rate slightly higher than 18 on July 16, while observations with 10x80 binoculars revealed a maximum rate near 33 on July 15. In all, 839 meteor paths were plotted during 8 nights of actual observations, and the observations revealed two radiants were present, although only the right ascension could be determined precisely: one radiant had α=278.7°, while the other was at α=300.5°. The authors concluded that the latter right ascension corresponded with the antisolar point, but they believed the former right ascension's declination "cannot be too high...."

Fortunately, the telescopic shower had been independently discovered in 1958, by V. V. Martynenko (USSR). Observing at Simferopol, he had observed a very strong telescopic shower, for which he was able to determine a radiant of α=277.5°, δ=+39° for July 9-10.

During 1969, members of the Crimean Yaroslavl and Dnepropetrovsk amateur astronomer societies participated in a visual and telescopic study of the Alpha Lyrids. One of the shower's original discoverers, Martynenko, coordinated the survey with the help of N. I. Bondar, N. M. Kremneva and V. V. Frolov. Meteors from this stream were detected during July 9-19, with the greatest activity coming during July 11-16. Based on 19 radiants determined from the plots of 825 visual and telescopic meteors, the average position was α=280.9°, δ=37.8°. The radiant diameter was generally given as two degrees, and the general direction of the radiant's daily motion was to the southeast. The meteors were described as white and fast, with an average magnitude of 4.1. During the period of observation the authors concluded that the Alpha Lyrids were "one of the most active showers in the range of bright stellar magnitudes, up to 3.5m, inclusively, and the most active in the faint range, 3m-6m."

Previous observations of this shower seem to be nonexistent. No trace of activity is present in any of the 19th Century publications, nor does convincing evidence exist in C. Hoffmeister's Meteorströme and the records of the American Meteor Society. According to Robert Mackenzie (director of the British Meteor Society) the visual ZHR of this shower reaches 1.5.

In an attempt to establish the orbit of this stream, the Author has searched through the lists of photographic and radar meteor orbits. No possible candidates were found among the first group of orbits, but three radar orbits were found. These meteors had been detected during July 15-19, 1969, by Z. Sekanina during the 1968-1969 session of the Radio Meteor Project and revealed an average radiant of α=286.8°, δ=35.5°.