K2ephem 1.1.1

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 |PyPI| |PyPI| |Travis status| |DOI|
===========================================

***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

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}
}

.. |PyPI| image:: http://img.shields.io/pypi/v/K2ephem.svg
:target: https://pypi.python.org/pypi/K2ephem/
.. |PyPI| image:: http://img.shields.io/pypi/dm/K2ephem.svg
:target: https://pypi.python.org/pypi/K2ephem/
.. |Travis status| image:: https://travis-ci.org/KeplerGO/K2ephem.svg
:target: https://travis-ci.org/KeplerGO/K2ephem
.. |DOI| image:: https://zenodo.org/badge/doi/10.5281/zenodo.44363.svg
:target: http://dx.doi.org/10.5281/zenodo.44363