Znojil's further analysis revealed that the northern branch consistently produced fainter meteors than the southern, with the average difference amounting to 1.02 magnitude. Both radiants possessed a spread in right ascension amounting to 5 deg, while their declinations covered only 2 deg of the sky. Many of the above features just discussed reveal an interesting structure for the Orionids. They demonstrate what may be expected to occur within an old meteor stream. Although observations of hourly rates are one way to detect filaments, future detections might be made in the study of average magnitudes and the percentages of meteors leaving persistent trains.
Some recent observations follow.
Lunsford Personal Comm. Studies of the evolution of the Orionid shower possess a strong interest due to the stream's link to Halley's comet. This link was indirectly made in 1911, when Charles P. Olivier mentioned the similarity between the orbit of the Orionids and that of the Eta Aquarids of May. Porter considered the 0.15 AU separation between the comet's orbit and Earth's orbit enough of a deterrent to make a connection with the Orionids impossible. Although others agreed with Porter's hypothesis, the similarity in the characteristics of the Orionid and Eta Aquarid meteors and activity rates was considered uncanny.