Reports from Geisei Observatory <January 24, 2008>

46P/Wirtanen, 8P/Tuttle, 29P/Schwassmann-Wachmann 1, and 17P/Holmes

    We are experiencing a very strong cold snap. The following are the results of the observation made on January 24 at Geisei Observatory:

46P/Wirtanen                                                 
2008UT       m1  dia. DC  Trans  Seeing   Inst.       Obs.   
Jan.24.39   8.5   4′  5   5/5    3/5     20cmR 60x  T.Seki  

8P/Tuttle                                                    
Jan.24.40   7.3   6′  6   5/5    3/5     20CMR 60x          

29P/Schwassmann-Wachmann 1                                   
Jan.24.42  12.0   2′  7   8/8    4/5     20cmR 60x          

17P/Holmes                                                   
Jan.24.43   4.5   ?    2   5/5    4/5     8x35B              

    The wintry monsoonal wind made seeing poor, but sky transparency was excellent.
I saw 46P/Wirtanen glowing in the twilight for the first time. 8P/Tuttle was -35 degrees south, very low in the southern sky, but the coma was very firm. 29P/Schwassmann-Wachmann 1 was faint in the 20cm telescope. In photographs, small faint glow envelopes the sharp nucleus. At one time it appeared as a bright large disk, but its activity seems to have settled down. 　
    I observed 17P/Holmes last. It was very close to bright Beta Persei and its presence was obvious to the naked eye. The coma, diffused and faint, was definitely larger than 1 degree in diameter. However, I was not able to measure it because of distraction by the bright light of the neighboring 2nd magnitude star. The 60cm telescope could capture just the 16th-magnitude nucleus and its immediate vicinity. The coma spreads throughout the one-degree-wide field of the camera and is vague.