adam-fo

A Python wrapper for Find_Orb orbit determination software, designed to work seamlessly with adam_core.

Overview

adam-fo provides a Python interface to Bill Gray's Find_Orb orbit determination software, allowing you to:

• Determine orbits from ADES-formatted observations
• Get orbit state vectors and covariance matrices in adam_core format
• Identify rejected observations from the orbit determination process

Installation

1. First, install the package using your preferred Python package manager:

pip install adam-fo

2. After installation, you need to build Find_Orb and its dependencies. Run:

build-fo

This will:

• Clone and build required repositories (lunar, sat_code, jpl_eph, find_orb, miscell)
• Download necessary ephemeris files
• Install everything in your XDG data directory (typically ~/.local/share/adam_fo)

Usage

Here's a basic example of using adam-fo with adam_core:

from adam_fo import fo
from adam_core.observations import ADESObservations

# Load your ADES-formatted observations
ades_string = """
# Example ADES PSV format
# version=2017
permID|trkSub|mode|stn|obsTime|ra|dec|rmsRA|rmsDec|astCat
|2020_CD3|CCD|F51|2020-02-18T10:11:22.000|180.5876|10.4789|0.15|0.15|Gaia2
"""

# Run orbit determination
orbits, rejected_observations, error = fo(ades_string)

if error is None:
    print(f"Successfully determined {len(orbits)} orbit(s)")
    print(f"Number of rejected observations: {len(rejected_observations)}")
    
    # Access orbit parameters (in ecliptic coordinates)
    coords = orbits.coordinates
    print("State vector at epoch:")
    print(f"Position (AU): {coords.x[0]}, {coords.y[0]}, {coords.z[0]}")
    print(f"Velocity (AU/day): {coords.vx[0]}, {coords.vy[0]}, {coords.vz[0]}")
    
else:
    print(f"Orbit determination failed: {error}")

Key Features

1. ADES Format Support: Works with ADES-formatted observations, the standard format for minor planet astrometry.

2. adam_core Integration: Returns results as adam_core objects:

   • Orbits in adam_core.orbits.Orbits format
   • Rejected observations in adam_core.observations.ADESObservations format

3. Covariance Information: Includes full 6x6 covariance matrices for orbit uncertainty analysis.

4. Automatic Setup: Handles Find_Orb installation and configuration automatically.

Configuration

Find_Orb configuration is handled through environment variables and configuration files:

• Default configuration is stored in the installed package
• Custom configuration can be placed in ~/.local/share/adam_fo/find_orb/find_orb/environ.dat
• Ephemeris files are automatically downloaded and configured

Notes

• Orbit state vectors are returned in ecliptic coordinates centered on the Sun
• Times are in TT (Terrestrial Time) scale
• Positions are in AU and velocities in AU/day
• Covariance matrices correspond to the cartesian state vector

Requirements

• Python 3.11+
• adam_core
• Build tools (gcc, make)
• Git

License

This project is licensed under the GPL License to be compatible with Find_Orb itself.