Jump to top page

Reports from Geisei Observatory <September 9, 2007>

Emails from Mr. Machholz and a photograph of C/1988 (Machholz)

    Mr. Don Machholz, a famous American comet hunter, asked me through Mr. Eiji Kato of Australia for a photograph of Comet Machholz C/1992 N1 he had discovered. It is a 15-year-old photograph and was taken at Geisei under extremely poor conditions. The observation of this comet spanned less than a week with only 9 observations made to determine its orbit, two of which were not up to scratch.

    At Geisei only two observations were made on each of July 9 and 10, 1992. Because there were so few observations made, I decided to find the photographs to make more precise measurements. I searched every corner of the old storage and checked thousands of negatives and prints without any success. Instead of what I was looking for, I found two photographs of the comets Mr. Machholz had discovered: C/1978 R3 and C/1988 P1. I decided to send him those photographs. As the photograph of C/1988 P1 was particularly bright and clear, I measured it again for its more precise position. This comet was discovered in the south of Taurus in the predawn sky on August 6 at 8th magnitude. There were 5 independent discoverers in Japan, but it does not bear their names.

    The photograph below was made by Metcalf guiding method on August 19 using the 60cm reflector. It was 7-8th magnitude visually.
C/1988 P1                                             
1988UT           RA (2000.0) decl.          m1        
Aug.19.78576  06 20 42.38  -00 35 52.8     8.1     372
    19.79826  06 20 49.06  -00 35 57.4     8.0     372

C/1988 P1 (Machhplz)
7-minute exposure from 18:55, August 18, 1988, U.T.
60cm f/3.5 reflector, TMY 400 film
Gisei Observatory (372)

Copyright (C) 2007 Tsutomu Seki.