Comments and Notes on the NEOCP

These temporary designations and ephemerides must not be promulgated.

In light of the recent increase in comet discoveries, many of which have appeared initially on this NEO Confirmation Page, there is a need for accurate astrometry between the time the object appears on an IAUC (and is hence removed from the Confirmation Page) and the time that the first orbit is published. The Confirmation Page has now been extended so that observers may continue to get ephemerides for newly-discovered comets without published orbits.

• If possible, observations should be made over an arc of several hours during the course of at least one night.
• When local circumstances are displayed, the azimuths are reckoned westwards from the south meridian.
• Objects will remain on this page until there is sufficient material to allow the preparation of an MPEC. If objects remain unconfirmed, they will normally be removed (and noted as being lost) five days after the initial posting.
• Ephemerides are in Universal Time (UT).
• Ephemerides can be generated for the geocenter, for a specific observatory code or for a user-specified site on the earth.
• For single-nighters, uncertainty maps and/or tables of offsets can be generated.
  The uncertainty maps include an indication of objects that are close to the earth. Three colors are used to indicate objects at various distances:
  • green, for objects that are more then 0.05 AU from the earth at the time used for the uncertainty map;
  • orange (supposedly) for objects between 0.05 and 0.01 AU from the earth
  • red, for objects within 0.01 AU.
  On the list of offset coordinates, variant ephemeris positions that are orange on the map are flagged by "!" and positions that are red on the map are flagged by "!!".
  In addition, the NEOCP now flags those variant orbits that will be coming within 0.0027 AU (roughly one lunar distance) sometime in the next 100 hours. Such objects will be shown in black on the uncertainty maps and flagged with "***" on the lists of offset coordinates.
  Counts of the number of variant orbits in each of the four flagged categories are now displayed to the right of the uncertainty plot.
• Potentially very small objects (with H fainter than 22.0) are indicated for the benefit of photometric observers by inclusion of an asterisk in the ephemeris header line between `U.T.' and `R.A.'.
• When observer comments are displayed, the column marked 'ONS' indicates whether or not the object was a one-nighter at the time the comment was submitted.
• When a removed object is flagged as `does not exist', it means that the object was retracted by the observer. If flagged as `lost', it means that either the object exists but was not confirmed, or that it does not exist. Presumably some sizeable fraction of the objects flagged as `lost' are really 'does not exist' cases.

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