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
|
.help map Jun99 "Slalib Package"
.nf
SUBROUTINE slMAP (RM, DM, PR, PD, PX, RV, EQ, DATE, RA, DA)
- - - -
M A P
- - - -
Transform star RA,Dec from mean place to geocentric apparent
The reference frames and timescales used are post IAU 1976.
References:
1984 Astronomical Almanac, pp B39-B41.
(also Lederle & Schwan, Astron. Astrophys. 134,
1-6, 1984)
Given:
RM,DM dp mean RA,Dec (rad)
PR,PD dp proper motions: RA,Dec changes per Julian year
PX dp parallax (arcsec)
RV dp radial velocity (km/sec, +ve if receding)
EQ dp epoch and equinox of star data (Julian)
DATE dp TDB for apparent place (JD-2400000.5)
Returned:
RA,DA dp apparent RA,Dec (rad)
Called:
slMAPA star-independent parameters
slMAPQ quick mean to apparent
Notes:
1) EQ is the Julian epoch specifying both the reference
frame and the epoch of the position - usually 2000.
For positions where the epoch and equinox are
different, use the routine slPM to apply proper
motion corrections before using this routine.
2) The distinction between the required TDB and TT is
always negligible. Moreover, for all but the most
critical applications UTC is adequate.
3) The proper motions in RA are dRA/dt rather than
cos(Dec)*dRA/dt.
4) This routine may be wasteful for some applications
because it recomputes the Earth position/velocity and
the precession/nutation matrix each time, and because
it allows for parallax and proper motion. Where
multiple transformations are to be carried out for one
epoch, a faster method is to call the slMAPA routine
once and then either the slMAPQ routine (which includes
parallax and proper motion) or slMAPZ (which assumes
zero parallax and proper motion).
P.T.Wallace Starlink 19 January 1993
Copyright (C) 1995 Rutherford Appleton Laboratory
Copyright (C) 1995 Association of Universities for Research in Astronomy Inc.
.fi
.endhelp
|
