K2ephem 1.2.0

Check if a Solar System object is (or was) observable by NASA's K2 mission. This command will query JPL/Horizons to find out.

K2ephem [](https://pypi.python.org/pypi/K2ephem/) [](https://pypi.python.org/pypi/K2ephem/) [](https://travis-ci.org/KeplerGO/K2ephem) [](http://dx.doi.org/10.5281/zenodo.44363)
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***Checks whether a Solar System body is (or was) observable by [NASA's
K2 mission](http://keplerscience.arc.nasa.gov).***

[NASA's K2 mission](http://keplerscience.arc.nasa.gov) is using the
unique assets of the repurposed Kepler space telescope to perform
long-baseline, high-cadence, high-precision photometry of targets
selected by the community. Unlike the original Kepler mission, the loss
of two reaction wheels requires K2 to point near the ecliptic plane. As
a result, K2 can provide high-precision lightcurves for large numbers of
asteroids, comets, and (dwarf) planets.

This repository provides a command-line tool that uses the JPL/Horizons
service to check whether a Solar System body is (or was) in the
footprint of one of the past or future [K2 Campaign
fields](http://keplerscience.arc.nasa.gov/k2-fields.html).

Installation
------------

You need to have a working version of Python installed. If this
requirement is met, you can install the latest stable version of
`K2ephem` using pip:

$ pip install K2ephem

If you have a previous version installed, you can upgrade it using:

pip install K2fov --upgrade

Or you can install the most recent development version from the git
repository as follows:

$ git clone https://github.com/KeplerGO/K2ephem.git
$ cd K2ephem
$ python setup.py install

The `setup.py` script will automatically take care of installing two
required dependencies (`K2fov` and `pandas`).

Usage
-----

After installation, you can call `K2ephem` from the command line. For
example, to verify whether comet *Chiron* can be observed by K2, simply
type:

K2ephem Chiron

Or you can type `K2ephem --help` to see the detailed usage instructions:

$ K2ephem --help
usage: K2ephem [-h] [--first campaign] [--last campaign] target

Check if a Solar System object is (or was) observable by NASA's K2 mission.
This command will query JPL/Horizons to find out.

positional arguments:
target Name of the target. Must be known to JPL/Horizons.

optional arguments:
-h, --help show this help message and exit
--first campaign First campaign to check (default: 0)
--last campaign Final campaign to check (default: 18)

Background
----------

The [JPL/Horizons](http://ssd.jpl.nasa.gov/horizons.cgi) ephemeris
service allows users to predict the position of Solar System bodies in
the sky as seen from the Kepler/K2 spacecraft. This can be achieved by
entering `@-227` as the "Observer Location". Setting the location to be
the Kepler spacecraft is *crucial*, because Kepler is more than 0.5 AU
away from the Earth!

Attribution
-----------

Created by Geert Barentsen for the NASA Kepler/K2 Guest Observer Office.

If this tool aided your research, please cite it using the [DOI
identifier](http://dx.doi.org/10.5281/zenodo.44363) or the following
BibTeX entry:

@misc{geert_barentsen_2016_44363,
author = {Geert Barentsen},
title = {K2ephem: v1.1.1},
month = jan,
year = 2016,
doi = {10.5281/zenodo.44363},
url = {http://dx.doi.org/10.5281/zenodo.44363}
}