1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
|
SUBROUTINE sla_TP2S (XI, ETA, RAZ, DECZ, RA, DEC)
*+
* - - - - -
* T P 2 S
* - - - - -
*
* Transform tangent plane coordinates into spherical
* (single precision)
*
* Given:
* XI,ETA real tangent plane rectangular coordinates
* RAZ,DECZ real spherical coordinates of tangent point
*
* Returned:
* RA,DEC real spherical coordinates (0-2pi,+/-pi/2)
*
* Called: sla_RANORM
*
* P.T.Wallace Starlink 24 July 1995
*
* Copyright (C) 1995 Rutherford Appleton Laboratory
*-
IMPLICIT NONE
REAL XI,ETA,RAZ,DECZ,RA,DEC
REAL sla_RANORM
REAL SDECZ,CDECZ,DENOM
SDECZ=SIN(DECZ)
CDECZ=COS(DECZ)
DENOM=CDECZ-ETA*SDECZ
RA=sla_RANORM(ATAN2(XI,DENOM)+RAZ)
DEC=ATAN2(SDECZ+ETA*CDECZ,SQRT(XI*XI+DENOM*DENOM))
END
|
