Gator Documentation:
Moving Object Search
Overview
It is possible to search for specific moving objects (typically solar system objects such as asteroids) using Gator. This function is sometimes referred to as a "precovery" search, looking for possible prior observations of a known target, whether or not that target was known or identified at the time the observation was made. This search mode is only available for selected catalogs having single-epoch position information within them, such as the WISE All-Sky Single Exposure (Level 1b) Source Table, where sources have both position and observation timestamp information. Gator will use the specified object's orbital parameters to calculate predicted/expected positions within the time range of the catalog of interest, and then perform a position+time match against the table. Additional constraints may be supplied by the user to further refine the match.
There are three solar system object/orbit search types:
Object Name
Search by object names by entering the name in the "Object Name" field. The accepted naming conventions are the ones that have been approved for use by the CSBN and its predecessors. News reports occasionally use unofficial or unapproved names: you cannot use these names to access objects. For asteroid names, one can enter either the ID number, name or designation, e.g. 2, 887, 1917, Pallas, Alinda, Cuyo, 1981 QB, 1996 GQ, or 2010 CG18. It can also handle names with apostrophes and dashes like O'Connell and Pic-du-Midi. For comet names, one can enter either the whole name e.g. 10P/Tempel 2, 73P-B/Schwassmann-Wachmann 3, P/2009 WJ50, or P/2010 D1 or just the unique part of its name e.g. 10P, 73P-B, 2009 WJ50, or 2010 D1.
MPC Input
Search for objects using a properly-formatted Minor Planet Center input string. This option allows the user to cut-and-paste a line directly from a table of orbital elements in MPC Format into the search field. There are a number of orbital element tables available at the MPC website, for example, observable NEO and observable comets. The complete list of minor planets can be found at the MPC Orbit (MPCORB) Database.
Information on the format of the element tables is given by following sites: minor planet format and comet format.
MPC One-line Element Input Examples:
ASTEROID: Icarus
| Designation | H | G | Epoch | M | w | Node | i | e | n | a |
| 01566 | 16.9 | 0.15 | K1128 | 78.13687 | 31.35339 | 88.02734 | 22.82772 | 0.8268277 | 0.88069351 | 1.0779191 |
COMET: C/2010 A4 (Siding Spring)
| Name/Design | Tp | q | e | w | Node | i | Epoch | H | G | Name |
| CK10A040 | 2010 10 8.7896 | 2.738033 | 0.990439 | 271.6989 |
346.6856 | 96.7301 | 20110208 | 12.5 | 4.0 | C/2010 A4 (Siding Spring) |
where e=eccentricity, a=semimajor axis, M=mean anomaly, i=inclination, Node=longitude of the ascending node, w=argument of perihelion, q=perihelion distance, Tp=time of perihelion passage, n=mean motion, H=absolute magnitude and G=slope parameter.
Orbit Element Input
The standard six orbital elements for asteroid are
- eccentricity,
- semimajor axis,
- mean anomaly,
- inclination,
- longitude of the ascending node, and
- argument of perihelion.
For comets, the elements are
- eccentricity,
- perihelion distance,
- time of perihelion passage,
- inclination,
- longitude of the ascending node, and
- argument of perihelion.
Notice that for comets, perihelion distance is used instead of semimajor axis and time of perihelion passage is used instead of mean anomaly. The reason for replacing these two parameters is to allow for cases where long period comets have a parabolic or hyperbolic orbit.
A good description of the orbital parameters are given in JPL's Solar System Dynamics web site.
Observation Time
A user has the option to fill in the specific observation begin and end time in UT or leave them blanck. In late case, default observation begin and end are assigned.
