rockfinder ∞
A python package and command-line suite to generate solar-system body ephemerides and to determine if specific transient dections are in fact known asteroids.
Here’s a summary of what’s included in the python package:
Classes
rockfinder.utKit.utKit |
Override dryx utKit |
Functions
rockfinder.jpl_horizons_ephemeris |
Given a known solar-system object ID (human-readable name, MPC number or MPC packed format) and one or more specific epochs, return the calculated ephemerides |
rockfinder.orbfit_ephemeris |
Given a known solar-system object ID (human-readable name or MPC number but NOT an MPC packed format) or list of names and one or more specific epochs, return the calculated ephemerides |
Installation ∞
The easiest way to install rockfinder is to use pip:
pip install rockfinder
Or you can clone the github repo and install from a local version of the code:
git clone git@github.com:thespacedoctor/rockfinder.git
cd rockfinder
python setup.py install
To upgrade to the latest version of rockfinder use the command:
pip install rockfinder --upgrade
Development ∞
If you want to tinker with the code, then install in development mode. This means you can modify the code from your cloned repo:
git clone git@github.com:thespacedoctor/rockfinder.git
cd rockfinder
python setup.py develop
Pull requests are welcomed!
Sublime Snippets ∞
If you use Sublime Text as your code editor, and you’re planning to develop your own python code with rockfinder, you might find my Sublime Snippets useful.
Command-Line Usage ∞
rockfinder can be used to generate ephemerides for your favourite asteroids
Usage:
rockfinder where [-eo] [csv|md|rst|json|yaml] <obscode> <objectId> <mjd>
Options:
obscode the observatory code to use for ephemeris generation
csv output results in csv format
md output results as a markdown table
rst output results as a restructured text table
json output results in json format
yaml output results in yaml format
-e, --extra return extra ephemeris info (verbose)
-o, --orbfit use orbfit instead of JPL to generate ephemerides (requires bespoke orbfit `ephem` executable)
-h, --help show this help message
Documentation ∞
Documentation for rockfinder is hosted by Read the Docs (last stable version and latest version).
Command-Line Tutorial ∞
Let’s say we want to generate an ephemeris for Ceres. We can either identify Ceres with its human-friendly name, its MPC number (1) or its MPC packed format (00001). I can grab an ephemeris from the JPL-Horizons for MJD=57967.564 with either of the following commands:
rockfinder where 1 57967.546
rockfinder where ceres 57967.546
rockfinder where 00001 57967.546
This returns the ephemeris in a neatly formatted table:
+-------------+-----------+----------+----------------+-----------------+---------------------+----------------------+---------------+------------------------+--------------------+--------------+
| mjd | ra_deg | dec_deg | ra_3sig_error | dec_3sig_error | ra_arcsec_per_hour | dec_arcsec_per_hour | apparent_mag | heliocentric_distance | observer_distance | phase_angle |
+-------------+-----------+----------+----------------+-----------------+---------------------+----------------------+---------------+------------------------+--------------------+--------------+
| 57967.5460 | 100.2386 | 24.2143 | 0.0000 | 0.0000 | 61.8963 | 0.8853 | 8.9100 | 2.6668 | 3.4864 | 11.2662 |
+-------------+-----------+----------+----------------+-----------------+---------------------+----------------------+---------------+------------------------+--------------------+--------------+
To make the results returned from Horizons a little more verbose, use the -e flag:
rockfinder where -e ceres 57967.546
+-------------+-----------+----------+----------------+-----------------+---------------------+----------------------+---------------+------------------------+----------------------+--------------------+------------------+--------------+---------------------+---------------------+-----------------------+-----------------------+----------------------------------+----------------------------+---------------------------+
| mjd | ra_deg | dec_deg | ra_3sig_error | dec_3sig_error | ra_arcsec_per_hour | dec_arcsec_per_hour | apparent_mag | heliocentric_distance | heliocentric_motion | observer_distance | observer_motion | phase_angle | true_anomaly_angle | surface_brightness | sun_obs_target_angle | sun_target_obs_angle | apparent_motion_relative_to_sun | phase_angle_bisector_long | phase_angle_bisector_lat |
+-------------+-----------+----------+----------------+-----------------+---------------------+----------------------+---------------+------------------------+----------------------+--------------------+------------------+--------------+---------------------+---------------------+-----------------------+-----------------------+----------------------------------+----------------------------+---------------------------+
| 57967.5460 | 100.2386 | 24.2143 | 0.0000 | 0.0000 | 61.8963 | 0.8853 | 8.9100 | 2.6668 | -1.2317 | 3.4864 | -13.2972 | 11.2662 | 294.8837 | 6.5600 | 30.8803 | 11.2614 | L | 93.6995 | 1.2823 |
+-------------+-----------+----------+----------------+-----------------+---------------------+----------------------+---------------+------------------------+----------------------+--------------------+------------------+--------------+---------------------+---------------------+-----------------------+-----------------------+----------------------------------+----------------------------+---------------------------+
To return an ephemeris covering multiple epoch, simply append extra MJD values to the command:
rockfinder where ceres 57967.546 57970.146 57975.683 57982.256 57994.547
+-------------+-----------+----------+----------------+-----------------+---------------------+----------------------+---------------+------------------------+--------------------+--------------+
| mjd | ra_deg | dec_deg | ra_3sig_error | dec_3sig_error | ra_arcsec_per_hour | dec_arcsec_per_hour | apparent_mag | heliocentric_distance | observer_distance | phase_angle |
+-------------+-----------+----------+----------------+-----------------+---------------------+----------------------+---------------+------------------------+--------------------+--------------+
| 57967.5460 | 100.2386 | 24.2143 | 0.0000 | 0.0000 | 61.8963 | 0.8853 | 8.9100 | 2.6668 | 3.4864 | 11.2662 |
| 57970.1460 | 101.4080 | 24.2238 | 0.0000 | 0.0000 | 61.6860 | -0.0088 | 8.9100 | 2.6649 | 3.4666 | 11.7406 |
| 57975.6830 | 103.8887 | 24.2210 | 0.0000 | 0.0000 | 60.6418 | -0.3915 | 8.9200 | 2.6610 | 3.4221 | 12.7383 |
| 57982.2560 | 106.8029 | 24.1784 | 0.0000 | 0.0000 | 60.9023 | -1.6280 | 8.9200 | 2.6565 | 3.3653 | 13.8893 |
| 57994.5470 | 112.1475 | 24.0019 | 0.0000 | 0.0000 | 58.6741 | -2.6660 | 8.9100 | 2.6481 | 3.2476 | 15.9324 |
+-------------+-----------+----------+----------------+-----------------+---------------------+----------------------+---------------+------------------------+--------------------+--------------+
The command-line version of rockfinder has the ability to output the ephemeris results in various formats (csv, json, markdown table, restructured text table, yaml, ascii table). State an output format to render the results:
rockfinder where -e json ceres 57967.546
[
{
"apparent_mag": 8.91,
"apparent_motion_relative_to_sun": "L",
"dec_3sig_error": 0.0,
"dec_arcsec_per_hour": 0.885313,
"dec_deg": 24.2142655,
"heliocentric_distance": 2.666789121428,
"heliocentric_motion": -1.231677,
"mjd": 57967.54600000009,
"observer_distance": 3.48635600851733,
"observer_motion": -13.2971761,
"phase_angle": 11.2662,
"phase_angle_bisector_lat": 1.2823,
"phase_angle_bisector_long": 93.6995,
"ra_3sig_error": 0.0,
"ra_arcsec_per_hour": 61.89635,
"ra_deg": 100.2386357,
"sun_obs_target_angle": 30.8803,
"sun_target_obs_angle": 11.2614,
"surface_brightness": 6.56,
"true_anomaly_angle": 294.8837
}
]
Python Package Documentation