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Reports from Geisei Observatory <July 24, 2005>


Magnitude of 161/Hartley-IRAS and observational data of C/2001 Q4 (NEAT), C/2004 Q1 (Tucker), P/2005 JQ5 (Catalina), 32P/Comas Sola, 69P/Taylor, 162P/Siding Spring, and 161P/Hartley-IRAS

    The following are the data of observations at Geisei Observatory, which haven't been reported previously:

    The brightness of 161/Hartley-IRAS is particularly noteworthy. One prediction gives a bright 8-9th magnitude around July 14 using the formula m1=5.5+5 log Δ+17.0 log R. However, the comet is not detectable visually. Even in the 60cm reflector it was faint and estimated to be at 14-15th magnitude. This formula was well tested by research and observation and is supposed to be accurate, but the results sometimes betray the predictions. I worked out the formula m1=9.5+5 log Δ+15 log R, based on the standard formula, in which the coefficient of log R is 10 or 15. The results from this formula will not deviate much from the prediction. The magnitude prediction of the comet is not easy. It often turns out to be wrong even though a well tested formula is used. This comet is very diffused without a nucleus and looks like a glowing fog.
    CK01Q040   2004 11 29.38299 19 28 16.01 +67 01 15.1          14.2 T      372

    CK04Q010   2004 11 29.41042 23 44 03.96 +39 29 33.4          11.5 T      372
    CK04Q010   2004 11 29.42326 23 44 02.80 +39 29 41.7                      372

    PK05J05Q   2005 06 06.53056 13 45 48.36 +06 17 00.8                      372

0032P          2004 11 29.41563 02 35 47.55 +11 40 57.8          12.8 T      372
0032P          2004 11 29.41927 02 35 47.35 +11 40 57.8                      372

0069P          2005 01 17.65556 09 06 27.70 +28 11 54.2          16.8 T      372
0069P          2005 02 02.55764 08 57 34.27 +33 09 24.7          16.5 T      372

0162P          2004 11 16.53715 22 56 04.72 -04 05 00.5          15.5 T      372
0162P          2004 11 29.40347 23 13 16.40 +10 55 52.5                      372
0162P          2004 11 29.42917 23 13 18.57 +10 57 29.3          13.4 T      372

0161P          2005 07 14.68715 04 43 01.23 +78 35 41.4          14.5 T      372
0161P          2005 07 14.76997 04 44 48.76 +78 40 02.5          14.4 T      372
Copyright (C) 2005 Tsutomu Seki.