Return to Orbit Comparison Tool
The orbit comparison tool allows the community to visualize and compare orbits computed by the largest orbit computing centers, such as the MPC, JPL/CNEOS, Lowell Astorb, ESA NEO Coordination Center and NEO Fixer. In this first iteration of the comparison tool, we focus on comparing NEA orbits in the MPC and JPL datasets. Data is downloaded weekly: MPCORB.dat is used for MPC orbits, the JPL APIs are used for JPL objects. All groups of solar system objects are classed according to an "orbit_type" value that largely maps to JPL's. For a detailed overview of these classes, see here.
The orbit comparison tool is being actively developed, and over the following months we intend to add data from different sources, include more filtering options, and include additional classes of objects.
Orbit Comparison Tool
The orbit comparison tool allows the community to visualize and compare orbits computed by the largest orbit computing centers, such as the MPC, JPL/CNEOS, Lowell Astorb, ESA NEO Coordination Center and NEO Fixer. In this first iteration of the comparison tool, we focus on comparing NEA orbits in the MPC and JPL datasets. Data is downloaded weekly: MPCORB.dat is used for MPC orbits, the JPL APIs are used for JPL objects. All groups of solar system objects are classed according to an "orbit_type" value that largely maps to JPL's. For a detailed overview of these classes, see here.
The orbit comparison tool is being actively developed, and over the following months we intend to add data from different sources, include more filtering options, and include additional classes of objects.
Usage
Below are explanations of fields found on the Orbit Comparison Tool:Group Dropdown
This allows you to show only objects belonging to specific orbit classes such as Atiras or Atens.Comparison Dropdown
This allows you to plot a specific orbital parameter.Y-Axis Dropdown
This allows you to change the y-axis values between two views:- JPL's values.
- The difference between MPC's and JPL's values. This can be helpful in identifying outliers.
Show Uncertainties Dropdown
This allows you to plot "whiskers" that correspond to the magnitude of JPL's uncertainty value (sigma) for the given comparison parameter.Optional "Third Axis" Dropdown
This allows you to color each point on the plot on a normalized scale, based on the value of an orbital parameter.Epoch Dropdown
This allows you to show only objects that are on the standard epoch (Ceres') or all objects across all epochs.Divergence Threshold
These fields allow you to subset the points on the plot to show only the points that differ by a given value. Supported syntax is as follows:- Numerical Value, e.g. 1.
Selects only those objects whose MPC and JPL values differ by at least 1 unit (e.g. 1 au in the case of semi-major axis) - Percentage Sign, e.g. 1%.
Selects only those objects whose MPC and JPL values differ by at least the specified percentage. - Sigma Threshold, e.g. 1s
Selects only those objects whose MPC and JPL values differ by at least the specified number of sigma-values.
For instance, 2s would show only points that differ by 2 times the sigma value of the given parameter.
For sigma thresholding, we refer to JPL's values for sigma-uncertainty.
This does not apply to arc length, number of observations, or magnitude values.
In the future, we will also be able to compare with MPC's sigma-uncertainty.