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Memorable Comets

Comet West
C/1975 V1-A (West)

Comet West in the 40cm reflector

    The tail of Comet West visible from 1975 to 76 was beautiful displaying remarkable variations. At times there were three tails and at other times it spread like a rainbow. The tail also took on an appearance of a thick rope of twisted strands extending upward. Although the tail showed great variations, it was never very long and well contained within a 3-degree field of the 40cm reflector. It was quite wide, but only 5 to 6 degrees long at most, I remember. In close-up images of the comet taken with Geisei's 40cm reflector in mid March, 1976, the tail showed great details. Usually such details could not be recorded on film by a small camera.

    Kodak's 103a glass photographic plates, used mainly by professional astronomers in those days, were excellent. The blue-sensitive 103a-O plate displayed extraordinary detail of the comet's blue tail. The 103a-E photographic plate, another Kodak product, was sensitive to red and captured gaseus nebulae superbly. Its excellent plate flatness also helped with accurate focusing. Camera lenses thought to be inferior otherwise were rejuvenated by the use of glass plates showing their real quality. The most serious problem was its price. Around 1990, when the production of this plate ceased, a 6x9cm plate cost as much as 800 yen. In those days we exposed at least 10 plates per night at Geisei and with this level of use, we could have ended up with an empty purse. However, Kodak ceased the production of the plates before the observatory could be forced into bankruptcy. Kodak failed to keep up with the times and new developments such as the popularity of CCD cameras. At Geisei Observatory the capability of the 60cm reflector, newly completed in 1980, combined with the 103a-O plate led us to the recovery of periodic comets and discovery of faint minor planets. And the 1986 apparition of Halley's Comet brought us quite an excitement.

6-minute exposure from 5:00, March 14, 1976 (J.S.T.)
40cm f/5 reflector, 103a-O plate

Copyright © 2006 Tsutomu Seki.