Routines to perform rotations on the celestial sphere and stereographic projection. More...
Prototypes | |
void | LALRotatePolarU (LALStatus *status, REAL8UnitPolarCoor *out, REAL8UnitPolarCoor *in, REAL8UnitPolarCoor *par) |
void | LALInvRotatePolarU (LALStatus *status, REAL8UnitPolarCoor *out, REAL8UnitPolarCoor *in, REAL8UnitPolarCoor *par) |
void | LALStereoProjectPolar (LALStatus *status, REAL8Polar2Coor *out, REAL8UnitPolarCoor *in) |
void | LALStereoProjectCart (LALStatus *status, REAL8Cart2Coor *out, REAL8UnitPolarCoor *in) |
void | LALStereoInvProjectPolar (LALStatus *status, REAL8UnitPolarCoor *out, REAL8Polar2Coor *in) |
void | LALStereoInvProjectCart (LALStatus *status, REAL8UnitPolarCoor *out, REAL8Cart2Coor *in) |
Routines to perform rotations on the celestial sphere and stereographic projection.
The function LALRotatePolarU() rotates the celestial sphere so that a given point, in the rotated coordinates, corresponds to ( \( \alpha = 0 \) , \( \delta = -\pi/2 \) ). The inputs are: *par
the reference point (e.g., the center of the sky-patch) of type REAL8UnitPolarCoor
and *in
the point on the celestial sphere we want to rotate. The output is *out
of type REAL8UnitPolarCoor
containing the coordinates of the point in the rotated reference frame.
The function LALInvRotatePolarU() does the inverse rotation. Given the reference point *par
(e.g., the center of the sky-patch) of type REAL8UnitPolarCoor
and a point *in
in the rotated reference frame, the output *out
are the coordinates of the point is the same reference system as *par
. All inputs and output being of type REAL8UnitPolarCoor
.
Given a point on the celestial sphere *in
of type REAL8UnitPolarCoor
, the function LALStereoProjectPolar() returns *out
, of type REAL8Polar2Coor
, the stereographic projection of that point in polar coordinates, with the particularity that out->radius
can be positive or negative. in->delta
= \( \pi/2 \) is an invalid argument and an error will output.
Given a point on the celestial sphere *in
of type REAL8UnitPolarCoor
, the function LALStereoProjectCart() returns *out
, of type REAL8Cart2Coor
, the stereographic projection of that point in Cartesian coordinates. in->delta
= \( \pi/2 \) is an invalid argument and an error will output.
Given a point on the projected plane *in
, the functions LALStereoInvProjectPolar() and LALStereoInvProjectCart() provide the corresponding point on the sphere *out
(corresponding to the inverse stereographic projection) of type REAL8UnitPolarCoor
.
Definition in file Stereographic.c.