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
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
|
.help plante Jun99 "Slalib Package"
.nf
SUBROUTINE slPLTE (DATE, ELONG, PHI, JFORM, EPOCH,
: ORBINC, ANODE, PERIH, AORQ, E,
: AORL, DM, RA, DEC, R, JSTAT)
- - - - - - -
P L T E
- - - - - - -
Topocentric apparent RA,Dec of a Solar-System object whose
heliocentric orbital elements are known.
Given:
DATE d MJD of observation (JD - 2400000.5)
ELONG d observer's east longitude (radians)
PHI d observer's geodetic latitude (radians)
JFORM i choice of element set (1-3; Note 4)
EPOCH d epoch of elements (TT MJD)
ORBINC d inclination (radians)
ANODE d longitude of the ascending node (radians)
PERIH d longitude or argument of perihelion (radians)
AORQ d mean distance or perihelion distance (AU)
E d eccentricity
AORL d mean anomaly or longitude (radians, JFORM=1,2 only)
DM d daily motion (radians, JFORM=1 only )
Returned:
RA,DEC d RA, Dec (topocentric apparent, radians)
R d distance from observer (AU)
JSTAT i status: 0 = OK
-1 = illegal JFORM
-2 = illegal E
-3 = illegal AORQ
-4 = illegal DM
-5 = numerical error
Notes:
1 DATE is the instant for which the prediction is required. It is
in the TT timescale (formerly Ephemeris Time, ET) and is a
Modified Julian Date (JD-2400000.5).
2 The longitude and latitude allow correction for geocentric
parallax. This is usually a small effect, but can become
important for Earth-crossing asteroids. Geocentric positions
can be generated by appropriate use of routines slEVP and
slPLNE.
3 The elements are with respect to the J2000 ecliptic and equinox.
4 Three different element-format options are available:
Option JFORM=1, suitable for the major planets:
EPOCH = epoch of elements (TT MJD)
ORBINC = inclination i (radians)
ANODE = longitude of the ascending node, big omega (radians)
PERIH = longitude of perihelion, curly pi (radians)
AORQ = mean distance, a (AU)
E = eccentricity, e
AORL = mean longitude L (radians)
DM = daily motion (radians)
Option JFORM=2, suitable for minor planets:
EPOCH = epoch of elements (TT MJD)
ORBINC = inclination i (radians)
ANODE = longitude of the ascending node, big omega (radians)
PERIH = argument of perihelion, little omega (radians)
AORQ = mean distance, a (AU)
E = eccentricity, e
AORL = mean anomaly M (radians)
Option JFORM=3, suitable for comets:
EPOCH = epoch of perihelion (TT MJD)
ORBINC = inclination i (radians)
ANODE = longitude of the ascending node, big omega (radians)
PERIH = argument of perihelion, little omega (radians)
AORQ = perihelion distance, q (AU)
E = eccentricity, e
5 Unused elements (DM for JFORM=2, AORL and DM for JFORM=3) are
not accessed.
Called: slGMST, slDT, slEPJ, slPVOB, slPRNU,
slPLNE, slDMXV, slDC2S, slDA2P
P.T.Wallace Starlink 17 March 1999
Copyright (C) 1999 Rutherford Appleton Laboratory
Copyright (C) 1995 Association of Universities for Research in Astronomy Inc.
.fi
.endhelp
|
