coordsys2euler_zyz


This routine returns the three Euler angles $\psi, \theta, \varphi
$, corresponding to a rotation between standard astronomical coordinate systems. This angles can then be used in rotate_alm

Location in HEALPix directory tree: src/f90/mod/coord_v_convert.f90 


FORMAT

call coordsys2euler_zyz( iepoch, oepoch, isys, osys, psi, theta, phi )


ARGUMENTS

name & dimensionality kind in/out description
       
iepoch DP IN epoch of the input astronomical coordinate system.
oepoch DP IN epoch of the output astronomical coordinate system.
isys(len=*) CHR IN input coordinate system, should be one of 'E'=Ecliptic, 'G'=Galactic, 'C'/'Q'=Celestial/eQuatorial.
osys(len=*) CHR IN output coordinate system, same choice as above.
psi DP OUT first Euler angle: rotation $\psi$ about the z-axis.
theta DP OUT second Euler angle: rotation $\theta$ about the original (unrotated) y-axis;
phi DP OUT third Euler angle: rotation $\varphi$ about the original (unrotated) z-axis;


EXAMPLE:

use coord_v_convert, only: coordsys2euler_zyz
use alm_tools, only: rotate_alm
...
call coordsys2euler_zyz(2000.0_dp, 2000.0_dp, 'E', 'G', psi, theta, phi)
call rotate_alm(64, alm_TGC, psi, theta, phi)
Rotate the alm from Ecliptic to Galactic coordinates.


RELATED ROUTINES

This section lists the routines related to coordsys2euler_zyz

rotate_alm
apply arbitrary sky rotation to a set of alm coefficients.
xcc_v_convert
rotates a 3D coordinate vector from one astronomical coordinate system to another.

Version 3.31, 2017-01-06