M. P. C. 24 597 1995 FEB. 15
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The MINOR PLANET CIRCULARS/MINOR PLANETS AND COMETS are published, on behalf
of Commission 20 of the International Astronomical Union, usually in batches
on the date of each full moon, by:
Minor Planet Center
Smithsonian Astrophysical Observatory
Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN@CFA.BITNET or .SPAN BRIAN@CFAPS1.SPAN GARETH@CFAPS1.SPAN
Brian G. Marsden, Director Gareth V. Williams, Associate Director
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EDITORIAL NOTICE.
It has been traditional to refrain from supplying in these {\it Circulars}
information about the accuracy of the orbital elements provided---and thus
of the ephemerides computed from them. Over the decades there has
developed the presumption that the orbital elements of numbered minor
planets are generally in good shape, that other multiple-opposition objects
require further observations before they can acquire such status, and that
orbits based on observations covering four days or less are scarcely worth
the paper on which they are printed. There has been a tendency to suppose
that astute readers can judge orbital reliability for themselves by
inspecting the residuals, considering not only size and possible systematic
effects, but also the extent and distribution of the observations used.
Fueled by suggestions that orbital accuracy should be indicated in a more
quantitative manner (e.g., Muinonen and Bowell 1993, {\it Icarus}
{\bf 104}, 255), the Minor Planet Center is introducing in this batch of
{\it Circulars} an ``uncertainty number'' $U$. This quantity, measured
on a logarithmic scale, is related to the possible in-orbit longitudinal
runoff with time and is represented by an integer from 0 (for a superbly
precise computation) to 9 (where the uncertainty can cover the whole sky).
Since a weak distribution of observations in a short-arc orbit and/or the
assumption of prescribed values for one or more of the orbital elements can
compromise the determination of $U$, we do not intend to publish $U$ numbers
for unperturbed orbit solutions, and it will not be given for comets because
of the largely unpredictable nature of nongravitational effects.
The $U$ values in this batch of {\it Circulars} range from 0 to 7. Among
the requirements for a new numbering of a minor planet is that $U \le 2$.
Small-to-moderate-field CCD observers wishing to record an unnumbered minor
planet at a {\it subsequent} opposition should probably only consider orbits
having $U \le 4$. Orbit computers who require details on the computation
of $U$ should contact the Minor Planet Center.
The last publication of ``one-night stands'', referring to ninor planets
observed only on single nights during the first half of 1992, appeared on
{\it MPC} 22366--22381. Since single-night observations made subsequently
are maintained in the Minor Planet Center's files, are used in the checking
processes, and are published when identifications with known objects are
found, it has been decided, in the interest of efficiency, no longer to
designate and publish them {\it en masse} in this manner. This decision
also applies to one-night stands observed prior to mid-1992.
* * * * *
ERRATA.
MPC Line
24134 3 For Malsutov read Maksutov
24251 -13 For Malsutov read Maksutov
24421 - 1 For 24310 read 24410
24422 - 7 For Malsutov read Maksutov
* * * * *
CORRECTED OBSERVATIONS.
The following observations correct those previously published.
Object Date UT R. A. (2000) Decl. Reference Mag. N Obs.
1983 RB2 1993 04 16.48568 12 13 09.89 +04 26 43.9 MPC 23379 17.5 413
1989 ST5 1989 11 02.26337 00 50 27.57 -01 41 17.3 MPC 15626 3 675
1989 ST5 1989 11 05.17326 00 49 14.12 -01 49 48.5 MPC 15626 2 675
1991 CM5 1991 01 18.38889 08 33 38.44 +15 32 03.0 MPC 20569 4 675
1991 CM5 1991 01 18.42291 08 33 36.05 +15 32 45.1 MPC 20569 4 675
Note 1: time changed slightly. 2: 1989 ST5 = (5928). 3 = 1 + 2.
4: 1991 CM5 = (5967).
* * * * *
IDENTIFICATION CHANGES.
Continuation to MPC 24252.
Object Date UT R. A. (2000) Decl. Old desig. Mag. N Obs.
1931 BR * 1931 01 26.43191 08 57 20.08 +26 38 58.4 1931 AG1 754
1987 SJ30 * 1987 09 22.90807 23 35 37.31 -12 47 28.6 1987 QA9 15.5 095
1991 DS2 * 1991 02 20.66561 10 12 09.59 +12 05 26.4 1991 CT2 17 898
1991 DS2 1991 02 20.68728 10 12 08.11 +12 05 38.2 1991 CT2 898
1993 HW7 * 1993 04 16.48568 12 19 52.62 +06 13 53.8 1993 FQ13 19.8 413
* * * * *
NUMBERING OF PERIODIC COMET.
Continuation to the list on MPC 24422.
117P/1989 T2 (Helin-Roman-Alu 1)
* * * * *
OBSERVATIONS OF COMETS.
Observations are published here for the following observatory codes:
046 Kle\v t. 0.57-m reflector + CCD and 0.63-m Maksutov telescope.
Observers J. Tich\'a, Z. Moravec and M. Tich\'y.
104 San Marcello Pistoiese. 0.40-m reflector + CCD. Observers L. Tesi
and A. Boattini.
108 Montelupo. 0.20-m f/10 reflector + CCD. Observers S. Bartolini
and M. Tombelli.
MPC