Giacobinid Meteors in 1939 and 1940?

Abstract

On October 9, 1933, when the earth passed through the region occupied eighty days earlier by the faint, short-period comet Giacobini-Zinner, the strongest meteor shower of the century appeared for a few hours. The best available orbit for the comet indicates that it will again pass near the earth's orbit on February 23, 1940; thus in 1939 the earth will precede the comet to the nodal point by 136 days and in 1940 follow it by 229 days. It therefore appears probable that some recurrence of the shower, but of a quite unpredictable intensity, may be anticipated on October 9 or 10 in either or both of these years¹. Observations from widely separated localities are of great value in the investigation of the internal structure of meteoric swarms, hence a request is made for reports from anyone detecting the shower. The radiant will be in the head of the constellation Draco, north and west of the bright star Vega. In 1939 the moon, aged twenty-five days, will not interfere; but in 1940, aged eight days, it will illuminate the evening sky.