Comments and Notes on the NEOCP
The NEOCP gives access to ephemerides for newly-discovered fast-moving
(or other unusual) objects in need of confirmation. Most of the objects
listed here have not yet received official provisional designations from the
Minor Planet Center, such objects are referenced
by their observer-assigned temporary designations.
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.