Reports from Geisei Observatory <December 8, 2004>

• 69P/Taylor, C/2004 U1 (LINEAR), C/2004 V5 (LINEAR-Hill)
We had another clear day today. I went to the observatory around midnight and persisted until morning.

First of all, I photographed 69P/Taylor with an exposure of 32 minutes using the Metcalf guiding method. This comet is near perihelion but faint at 17.5 magnitude. When it was recaptured by Kowal at Palomar in 1976 after having been missing for many years, it was at 16th magnitude showing a substantial coma. We captured this comet by the 40cm reflector at Geisei a little earlier, but unfortunately we were too late reporting our recovery.
This year, however, the comet seems to be declined to an extent that only the nucleus is confirmed seen with a smudge of light looking like a tail. This comet does not follow the calculated orbit precisely. There seems to be about 3" residuals against the reliable orbital elements calculated by Mr. Kenji Muraoka. Is it caused by a difficult non-gravitational effect?

I observed C/2004 U1, which has recently experienced an outburst and brightened to 13.5 magnitude, and C/2004 V5, which shows two nuclei. C/2003 V5 is still at 17.5 - 18.0 magnitude with the nucleus A followed by the nucleus B. The preceding nucleus A looks dragging the nucleus B with a thin glowing curved string. Checking the photograph taken in November, I thought it was a scratch on the film, but now it may be real.

As TP6415 has been gone, I have been trying to get the best results from the moderate-speed ISO100 film. Film of this speed delivers far better results for faint objects than the high-speed ISO 400 film. I expect to continue to struggle for some time, hanging on to and from the huge telescope like an artilleryman maneuvering his gigantic gun.

[Photo of 69P/Taylor]
69P/Taylor
Exposure 2:35 - 3:07 December 9 J.S.T.
60cm f/3.5 reflector
Fuji NEOPAN 100 ACROS