MPEC 2010-U20 : EDITORIAL NOTICEThe following Minor Planet Electronic Circular may be linked-to from your own Web pages, but must not otherwise be redistributed electronically.
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M.P.E.C. 2010-U20 Issued 2010 Oct. 19, 02:20 UT The Minor Planet Electronic Circulars contain information on unusual minor planets and routine data on comets. They are published on behalf of Commission 20 of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. Supported in part by the Steven and Michele Kirsch Foundation Prepared using the Tamkin Foundation Computer Network MPC@CFA.HARVARD.EDU URL http://cfa-www.harvard.edu/iau/mpc.html ISSN 1523-6714 EDITORIAL NOTICE The rules defining who discovered a particular object have evolved over the past two centuries. In the days of visual observation, discovery was credited to the first person to report an observation of a new object. If a subsequent report emerged of an earlier observation, the discovery credit was switched to the earlier observer. This reassignment of discovery credit was applied somewhat arbitrarily and there are a number of cases where earlier observations are simply listed as "prediscovery". Designations would be assigned on the basis on single-night approximate measures. When the Minor Planet Center (MPC) was founded, discoveries continued to be credited on the basis of single approximate positions (e.g., Minor Planet Circular 2). After the MPC moved to Cambridge in 1978, an Editorial Notice (Minor Planet Circular 4845-4846) informed observers that approximate observations were no longer eligible for discovery credit. In 1995, the decision was taken to no longer assign designations to single-night detections (Minor Planet Circular 24597). The Minor Planet Center (MPC) recently changed the way discovery credit was assigned to new discoveries. Rather than being the earliest observation in the initial two-night linkage, the discovery credit was to be given to the earliest observation at that opposition. In practice, it is often difficult to determine which observation is the earliest at the time the designation needs to be assigned. Effective immediately, the MPC will separate the concept of discovery credit from the assignment of asterisks. Asterisks will revert to being simply an indication of the initial assignment of a new designation and will not be associated with any discoverer. In addition, the MPC will begin adding timetags to all archived and newly-received observations, to indicate when they were received at the MPC. For the moment, these timetags will be maintained only on internal datasets. External availability of the timetags will depend on certain professional users of the observational datasets indicating that their software will cope with the extended format. For newly-submitted observations, the timetags will indicate when the observation was accepted by the AUTOACK routine. For previously-submitted observations, a timetag will be constructed that is related to the date of observation. Known cases of delayed submission of observations will be accounted for in these constructed timetags. Discoverers will be defined only when an object is numbered. At that time, the timetags on all the observations included in the solution will be examined. The discovery observation will be that observation which is the earliest-reported observations at the opposition with the earliest-reported second-night observation. The discovery observation will then define the discoverer. This scheme, which will be entirely automatic, is consistent with the following resolution adopted by Commission 20 at the 1979 IAU General Assembly: "The Commission defines the discovery as the earliest apparition at which an orbit useful in the establishment of identifications was calculated" (taken from Minor Planet Circular 4845-4846). The new scheme removes one common complaint with the current scheme: that the assignment of discovery credit depended, to some degree, on the ability of either the MPC or the observer to make the initial night-to-night linkages. In addition, it removes the apparent arbitrary nature of the order of designations in new identifications. Objects that have multiple-opposition orbits as of now will be grandfathered into the old scheme of assigning discovery credit. Timothy B. Spahr (C) Copyright 2010 MPC M.P.E.C. 2010-U20
- 1997-B01 (the full form)
- J97B01 (the packed version of the full form)
- B01 (the abbreviated form)