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
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
SUBROUTINE sla_EQGAL (DR, DD, DL, DB)
*+
* - - - - - -
* E Q G A L
* - - - - - -
*
* Transformation from J2000.0 equatorial coordinates to
* IAU 1958 galactic coordinates (double precision)
*
* Given:
* DR,DD dp J2000.0 RA,Dec
*
* Returned:
* DL,DB dp galactic longitude and latitude L2,B2
*
* (all arguments are radians)
*
* Called:
* sla_DCS2C, sla_DMXV, sla_DCC2S, sla_DRANRM, sla_DRANGE
*
* Note:
* The equatorial coordinates are J2000.0. Use the routine
* sla_EG50 if conversion from B1950.0 'FK4' coordinates is
* required.
*
* Reference:
* Blaauw et al, Mon.Not.R.Astron.Soc.,121,123 (1960)
*
* P.T.Wallace Starlink 21 September 1998
*
* Copyright (C) 1998 Rutherford Appleton Laboratory
*-
IMPLICIT NONE
DOUBLE PRECISION DR,DD,DL,DB
DOUBLE PRECISION sla_DRANRM,sla_DRANGE
DOUBLE PRECISION V1(3),V2(3)
*
* L2,B2 system of galactic coordinates
*
* P = 192.25 RA of galactic north pole (mean B1950.0)
* Q = 62.6 inclination of galactic to mean B1950.0 equator
* R = 33 longitude of ascending node
*
* P,Q,R are degrees
*
* Equatorial to galactic rotation matrix (J2000.0), obtained by
* applying the standard FK4 to FK5 transformation, for zero proper
* motion in FK5, to the columns of the B1950 equatorial to
* galactic rotation matrix:
*
DOUBLE PRECISION RMAT(3,3)
DATA RMAT(1,1),RMAT(1,2),RMAT(1,3),
: RMAT(2,1),RMAT(2,2),RMAT(2,3),
: RMAT(3,1),RMAT(3,2),RMAT(3,3)/
: -0.054875539726D0,-0.873437108010D0,-0.483834985808D0,
: +0.494109453312D0,-0.444829589425D0,+0.746982251810D0,
: -0.867666135858D0,-0.198076386122D0,+0.455983795705D0/
* Spherical to Cartesian
CALL sla_DCS2C(DR,DD,V1)
* Equatorial to galactic
CALL sla_DMXV(RMAT,V1,V2)
* Cartesian to spherical
CALL sla_DCC2S(V2,DL,DB)
* Express in conventional ranges
DL=sla_DRANRM(DL)
DB=sla_DRANGE(DB)
END
|
