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Reports from Geisei Observatory <August 17, 2006>

72P/Denning-Fujikawa remeasured

    This comet was discovered a long time ago. I found photographic plates of this comet at the back of the shelf which had been long forgotten. I have remeasured these plates and suspect that some have been measured for the first time. This is the lost comet Denning-Fujikawa.

    The comet was visually discovered by Denning of the U.K. in 1881. It is supposed to have been orbiting the sun in a 9-year period, but had not been recovered until Mr. Fujikawa chanced upon it in 1978. Since then, it must have orbited the sun three times. I searched for it frequently at Geisei using the 60cm reflector under favorable conditions but no success. The image of this comet shining in Leo in October 1978 is deeply etched in my mind. It was very diffused at 10th magnitude, but photographs taken by the 40cm "comet" telescope showed the nucleus quite clearly. In those days I only used 6x9cm glass photographic plates, mostly Fuji FLO-II plates. In those days I used the SAO Star Catalog and used three comparison stars, but for these new measurements as many as 9 stars were used. They are faint stars all close to the comet, so the measurements must be more accurate.
72P/Denning-Fujikawa(1978 T2)                         
1978UT           α (2000.0)   δ           m1         
Oct.11.80729  10 23 18.34  +07 06 33.5     9.6     372
    29.76806  10 16 41.30  +17 39 24.8    13.6     372
    29.78993  10 16 41.53  +17 39 52.7    12.6     372
    31.80799  10 17 21.11  +18 20 58.1    12.5     372
Nov. 2.80069  10 18 04.38  +18 58 36.8    13.3     372
    The photographs used for the new measurements were taken by the 40cm telescope on October 11, when the comet was at the brightest. Its image is perfectly round and the tail is completely invisible. Is this image really that of the lost comet which had been seen only once in one hundred years?

    My next report will be about another unlucky comet Haneda-Campos.

Comet Denning-Fujikawa
7-minute exposure from 4:19 on October 12, 1978
40cm f/5 reflector, FLO-II photographic plate

Refer to Reports from Geisei Observatory October 28, 2002
Copyright (C) 2006 Tsutomu Seki.