| 1 | #include "slalib.h"
|
|---|
| 2 | #include "slamac.h"
|
|---|
| 3 | void slaEcleq ( double dl, double db, double date,
|
|---|
| 4 | double *dr, double *dd)
|
|---|
| 5 | /*
|
|---|
| 6 | ** - - - - - - - - -
|
|---|
| 7 | ** s l a E c l e q
|
|---|
| 8 | ** - - - - - - - - -
|
|---|
| 9 | **
|
|---|
| 10 | ** Transformation from ecliptic coordinates to J2000.0
|
|---|
| 11 | ** equatorial coordinates.
|
|---|
| 12 | **
|
|---|
| 13 | ** (double precision)
|
|---|
| 14 | **
|
|---|
| 15 | ** Given:
|
|---|
| 16 | ** dl,db double ecliptic longitude and latitude
|
|---|
| 17 | ** (mean of date, IAU 1980 theory, radians)
|
|---|
| 18 | ** date double TDB (loosely ET) as Modified Julian Date
|
|---|
| 19 | ** (JD-2400000.5)
|
|---|
| 20 | ** Returned:
|
|---|
| 21 | ** *dr,*dd double J2000.0 mean RA,Dec (radians)
|
|---|
| 22 | **
|
|---|
| 23 | ** Called:
|
|---|
| 24 | ** slaDcs2c, slaEcmat, slaDimxv, slaPrec, slaEpj, slaDcc2s,
|
|---|
| 25 | ** slaDranrm, slaDrange
|
|---|
| 26 | **
|
|---|
| 27 | ** Last revision: 31 October 1993
|
|---|
| 28 | **
|
|---|
| 29 | ** Copyright P.T.Wallace. All rights reserved.
|
|---|
| 30 | */
|
|---|
| 31 | {
|
|---|
| 32 | double rmat[3][3], v1[3], v2[3];
|
|---|
| 33 |
|
|---|
| 34 | /* Spherical to Cartesian */
|
|---|
| 35 | slaDcs2c ( dl, db, v1 );
|
|---|
| 36 |
|
|---|
| 37 | /* Ecliptic to equatorial */
|
|---|
| 38 | slaEcmat ( date, rmat );
|
|---|
| 39 | slaDimxv ( rmat, v1, v2 );
|
|---|
| 40 |
|
|---|
| 41 | /* Mean of date to J2000 */
|
|---|
| 42 | slaPrec ( 2000.0, slaEpj ( date ), rmat );
|
|---|
| 43 | slaDimxv ( rmat, v2, v1 );
|
|---|
| 44 |
|
|---|
| 45 | /* Cartesian to spherical */
|
|---|
| 46 | slaDcc2s ( v1, dr, dd );
|
|---|
| 47 |
|
|---|
| 48 | /* Express in conventional ranges */
|
|---|
| 49 | *dr = slaDranrm ( *dr );
|
|---|
| 50 | *dd = slaDrange ( *dd );
|
|---|
| 51 | }
|
|---|