==================================
 Functions and constants in PyTPM
==================================

.. currentmodule:: pytpm.tpm 

Most of the functions in TPM can be called from PyTPM, using functions
of the same name. These call the TPM function of the same name, with
the arguments provided and returns the value returned by the TPM
function.

.. contents::

Functions
=========

Main TPM functions
------------------

.. autofunction:: tpm_state(s)
.. autofunction:: tpm_data(tstate, action)
.. autofunction:: proper_motion(v6, end, start)
.. autofunction:: tpm(pvec, s1, s2, ep, eq, tstate)

Functions in the convert module
-------------------------------

.. autofunction:: pytpm.convert.convertv6
.. autofunction:: pytpm.convert.precess 
.. autofunction:: pytpm.convert.precessv6
.. autofunction:: pytpm.convert.cat2v6
.. autofunction:: pytpm.convert.v62cat
.. autofunction:: pytpm.convert.proper_motion

Date and time calculations and conversions
------------------------------------------

The current Julian date can be calculated using the following two
functions. The first function returns a ``JD`` object and the second
returns a scalar. 

.. autofunction:: jd_now
.. autofunction:: utc_now

The following functions convert a Julian date into a Basselian year and
and vice-versa.

.. autofunction:: byear2jd(byear)
.. autofunction:: jd2byear(jd)

The following functions convert a Julian date into a Julian year and
vice-versa.

.. autofunction:: jyear2jd(jyear)
.. autofunction:: jd2jyear(jd)

The functions below convert a Gregorian calendar date and a Julian
calendar date into Julian dates.

.. autofunction:: gcal2j(year, month, day)
.. autofunction:: jcal2j(year, month, day)

The function ``j2dow()`` return the day of the week corresponding to
the given Julian date. 

.. autofunction:: j2dow(j)

The function ``y2doy()`` returns the number or days in the given year.

.. autofunction:: y2doy(j)

The following two functions convert a Julian date into a year with
fractional part.

.. autofunction:: j2y(j)
.. autofunction:: y2j(y) 

Conversion between time scales
------------------------------

.. autofunction:: delta_AT(utc)
.. autofunction:: delta_T(ut1)
.. autofunction:: delta_UT(utc)
.. autofunction:: delta_ET(utc)
.. autofunction:: delta_TT(utc)
.. autofunction:: tdt2tdb(tdt)
.. autofunction:: ut12gmst(ut1)    
.. autofunction:: et2tdt(et)
.. autofunction:: tai2tdt(tai)
.. autofunction:: tdt2et(tdt)
.. autofunction:: ut12et(ut1)
.. autofunction:: utc2et(utc)
.. autofunction:: utc2tdt(utc)
.. autofunction:: utc2ut1(utc)    
.. autofunction:: et2ut1(et)
.. autofunction:: et2utc(et)
.. autofunction:: tai2utc(tai)
.. autofunction:: tdt2tai(tdt)
.. autofunction:: tdt2utc(tdt)
.. autofunction:: ut12utc(ut1)
.. autofunction:: et2tai(et)
.. autofunction:: et2tdb(et)
.. autofunction:: tai2et(tai)
.. autofunction:: tai2tdb(tai)
.. autofunction:: tai2ut1(tai)
.. autofunction:: tdt2ut1(tdt)
.. autofunction:: ut12tai(ut1)
.. autofunction:: ut12tdb(ut1)
.. autofunction:: ut12tdt(ut1)
.. autofunction:: utc2tdb(utc)
.. autofunction:: et2ut(et)
.. autofunction:: ut2et(ut)
.. autofunction:: ut2gmst(ut)


Conversion of angles between different units
--------------------------------------------

The following functions are provided for converting angles between four
different units: degrees, arc-seconds, radians and hours. Many of these
conversions can also be performed by using ``DMS`` and ``HMS`` objects.

.. autofunction:: ndelta(delta, degrees=True)
.. autofunction:: nalpha(alpha, degrees=True)
.. autofunction:: d2d(d) 
.. autofunction:: h2h(h) 
.. autofunction:: r2r(r) 
.. autofunction:: d2h(d) 
.. autofunction:: h2d(h) 
.. autofunction:: d2r(d) 
.. autofunction:: r2d(r) 
.. autofunction:: h2r(h) 
.. autofunction:: r2h(r) 
.. autofunction:: d2as(d)
.. autofunction:: as2d(arcs) 
.. autofunction:: h2as(h) 
.. autofunction:: as2h(arcs) 
.. autofunction:: r2as(r) 
.. autofunction:: as2r(arcs) 

Formatting angles and dates
---------------------------

Formatted string representations of angles can be generated using the
following functions.

.. autofunction:: fmt_alpha(alpha)
.. autofunction:: fmt_d(d)
.. autofunction:: fmt_delta(delta)
.. autofunction:: fmt_h(h)
.. autofunction:: fmt_j(j)
.. autofunction:: fmt_r(r)
.. autofunction:: fmt_y(y)

Functions related to astrometry
===============================

.. autofunction:: cat2v6(ra, de, pmra, pmdec, px, rv, C=36525.0)
.. autofunction:: v62cat(v6, C=36525.0)
.. autofunction:: proper_motion(v6, end, start)
.. autofunction:: aberrate(p, e, flag)
.. autofunction:: azel2hadec(v6, latitude)
.. autofunction:: hadec2azel(v6, latitude)
.. autofunction:: evp(tdb)
.. autofunction:: ecl2equ(v6, obl)
.. autofunction:: equ2ecl(v6, obl)    
.. autofunction:: ellab(tdt, star, flag)
.. autofunction:: equ2gal(v6)    
.. autofunction:: gal2equ(v6)    
.. autofunction:: eterms(ep)
.. autofunction:: fk425(v6)
.. autofunction:: fk524(v6)
.. autofunction:: geod2geoc(lon, lat, alt)
.. autofunction:: ldeflect(star, earth, flag)
.. autofunction:: precess(start, end, v6, pflag)
.. autofunction:: eccentricity(tdt)
.. autofunction:: eccentricity_dot(tdt)
.. autofunction:: obliquity(tdt)
.. autofunction:: obliquity_dot(tdt)
.. autofunction:: refco(lat=0.557744205098, alt=2093.093, T=273.15, P=1013.25, rh=0.0, wavelength=0.550, eps=1e-8)
.. autofunction:: refract(zx, refa, refb, flag)
.. autofunction:: solar_perigee(tdt)
.. autofunction:: solar_perigee_dot(tdt)
.. autofunction:: theta(start, end, pflag)
.. autofunction:: thetadot(start, end, pflag)
.. autofunction:: zee(start, end, pflag)
.. autofunction:: zeedot(start, end, pflag)
.. autofunction:: zeta(start, end, pflag)
.. autofunction:: zetadot(start, end, pflag)
.. autofunction:: nutations(tdt)

Functions for creating matrices
===============================

.. autofunction:: m3rx
.. autofunction:: m3rxdot 
.. autofunction:: m3ry 
.. autofunction:: m3rydot 
.. autofunction:: m3rz 
.. autofunction:: m3rzdot 
.. autofunction:: m6qx
.. autofunction:: m6qy 
.. autofunction:: m6qz 


.. _tpm_constants:

Constants
=========

Some frequently used constants. There are several more constants
available, but they are mostly for internal use. See TPM headers and
manual for more information on these.

+---------+--------------------------------------------------+
|M_PI     |Pi                                                |
+---------+--------------------------------------------------+
|MJD_0    |Starting point for modified Julian dates.         |
+---------+--------------------------------------------------+
|B1950    |Epoch B1950.0.                                    |
+---------+--------------------------------------------------+
|J2000    |Epoch J2000.0.                                    |
+---------+--------------------------------------------------+
|J1984    |Epoch J1984.0.                                    |
+---------+--------------------------------------------------+
|CB       |Number of days in a Besselian century.            |
+---------+--------------------------------------------------+
|CJ       |Number of days in a Julian century.               |
+---------+--------------------------------------------------+



..  LocalWords:  autofunction currentmodule pytpm tpm