This is an apparently strong telescopic meteor shower with a duration
extending from July 9-20. When at maximum on July 14 (solar longitude=112 deg),
the radiant is located at RA=280 deg, DEC=+38 deg. 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 deg in diameter.
History
The Alpha Lyrids were discovered in July 1958, during a Czechoslovakian
meteor expedition to Mount Bezovec. Jiri Grygar, Lubos Kohoutek, Zdenek Kviz and
Jaromir 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 RA=278.7
deg, while the other was at RA=300.5 deg. 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
RA=277.5 deg, DEC=+39 deg 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 RA=280.9 deg, DEC=37.8
deg. 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 Cuno 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 Zdenek
Sekanina during the 1968-1969 session of the Radio Meteor Project and revealed
an average radiant of RA=286.8 deg, DEC=35.5 deg.
Orbit
The three radar meteors found by the Author among the 39,145 orbits obtained
by Sekanina were averaged to reveal the following orbit.