Circular No. 6965

Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION

Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.

IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)

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Phone 617-495-7244/7440/7444 (for emergency use only)

COMET C/1998 M6 (MONTANI)

Additional CCD astrometry:

1998 UT α_{2000} δ_{2000} m_{1} Observer
July 2.43232 20^{h}56^{m}20.^{s}71 −17^{o}16′30′′.5 18.9 Montani
2.43794 20 56 20.45 −17 16 29.4 19.0  _{”}
2.44355 20 56 20.15 −17 16 27.8 18.9  _{”}
2.65638 20 56 10.30 −17 15 40.2 18.3 Sugie
2.66054 20 56 10.04 −17 15 39.8  _{”}
2.66263 20 56 09.87 −17 15 39.5  _{”}

J. Montani (Kitt Peak). 0.9-m Spacewatch telescope. A. Sugie (Dynic Astronomical Observatory). 0.60-m f/3.7 reflector. Com-

municated by S. Nakano.

Very preliminary parabolic orbital elements by the undersigned from 15 observations, June 30–July 2:

T = 1997 Nov. 16.30 TT  ω = 337.^{o}46
Ω = 306.56 }2000.0
q = 5.7331 AU  i = 89.11
1998TT α_{2000}  δ_{2000}  Δ  r  ϵ  β  m_{1}
June 26 21^{h}01.^{m}22 −17^{o}40.^{′}1 5.119 5.949 141.^{o}6 6.^{o}1 18.3
July 1 20 57.46 −17 21.7 5.079 5.958 147.1 5.3 18.3
6 20 53.49 −17 03.5 5.046 5.968 152.7 4.5 18.3
11 20 49.33 −16 45.4 5.022 5.978 158.4 3.6 18.3
16 20 45.04 −16 27.4 5.005 5.988 164.0 2.7 18.3
21 20 40.64 −16 09.4 4.997 5.999 169.6 1.8 18.3
26 20 36.20 −15 51.4 4.997 6.009 174.8 0.9 18.3

COMET 88P/HOWELL Visual m_{1} estimates: Apr. 20.87 UT, 13.6 (K. Hornoch, Lelekovice,

Czech Republic, 0.35-m reflector); 23.95, 14.8 (M. Lehký, Hradec Králové, Czech Rep., 0.42-m reflector); May 17.86, 13.4 (M. Reszelski, Szamotuly, Poland, 0.25-m reflector); 22.92, 14.2 (K. Sárneczky, Ágasvár, Hungary, 0.44-m reflector); 31.91, 13.8 (Lehký); June 20.91, 13.2 (Lehký); 25.90, 12.4 (Hornoch); 28.19, 13.2 (A. Hale, Cloudcroft, NM, 0.41-m reflector).

1998 July 3  \begin{matrix}c \\ ◯ \end{matrix} Copyright 1998 CBAT  Daniel W. E. Green