# Licensed under a 3-clause BSD style license - see LICENSE.rst
# -*- coding: utf-8 -*-
"""
Defines a catch-all class for useful constants. These are meant to be
values that are **not** available elsewhere, such as
`astropy.constants`_.
----
.. include license and copyright
.. include:: ../include/copy.rst
----
.. include common links, assuming primary doc root is up one directory
.. include:: ../include/links.rst
"""
import numpy
[docs]
class DAPConstants:
r"""
Defines the following set of constants:
+-----------------------------+-------------------------------+
| Attribute | Value |
+=============================+===============================+
| :attr:`sig2fwhm` | :math:`\sqrt{8\ln(2)}` |
+-----------------------------+-------------------------------+
| :attr:`rad2arcs` | :math:`3600\frac{180}{\pi}` |
+-----------------------------+-------------------------------+
| :attr:`sidereal_year` | :math:`31558175.779` |
+-----------------------------+-------------------------------+
"""
# Convert from sigma to FWHM: FWHM = sig2fwhm * sig
sig2fwhm = numpy.sqrt(8.0 * numpy.log(2.0))
r"""
Conversion factor from the standard deviation, :math:`\sigma`, of
a Gaussian to its full-width at half maximum (FWHM).
"""
# Convert from radians to arcseconds: arcsec = rad2arcs * radians
rad2arcs = 60*60*180/numpy.pi
"""
Conversion factor from radians to to arcseconds.
"""
# Length of one sidereal year in seconds ()
sidereal_year = 31558175.779
"""
Length of a sidereal year (1.0000385 Gregorian years) in seconds.
"""
def __init__(self):
self.sig2fwhm = constants.sig2fwhm
self.rad2arcs = constants.rad2arcs
self.sidereal_year = constants.sidereal_year