From d54fe7c1f704a63824c5bfa0ece65245572e9b27 Mon Sep 17 00:00:00 2001 From: Joseph Hunkeler Date: Wed, 4 Mar 2015 21:21:30 -0500 Subject: Initial commit --- src/slalib/sun67.htx/node144.html | 310 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 310 insertions(+) create mode 100644 src/slalib/sun67.htx/node144.html (limited to 'src/slalib/sun67.htx/node144.html') diff --git a/src/slalib/sun67.htx/node144.html b/src/slalib/sun67.htx/node144.html new file mode 100644 index 0000000..eb511e6 --- /dev/null +++ b/src/slalib/sun67.htx/node144.html @@ -0,0 +1,310 @@ + + + + +SLA_PERTEL - Perturbed Orbital Elements + + + + + + + + + + + + +
+ +next + +up + +previous +
+ Next: SLA_PERTUE - Perturbed Universal Elements +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_PERMUT - Next Permutation +

+

+

SLA_PERTEL - Perturbed Orbital Elements +   +

+
+
ACTION: +
Update the osculating elements of an asteroid or comet by +applying planetary perturbations. +

CALL: +
CALL sla_PERTEL ( + JFORM, DATE0, DATE1, + EPOCH0, ORBI0, ANODE0, PERIH0, AORQ0, E0, AM0, + EPOCH1, ORBI1, ANODE1, PERIH1, AORQ1, E1, AM1, + JSTAT) +

+

+
GIVEN (format and dates): +
+
+ + + + + + + + + + + + + + + + + + + + + +
JFORMIchoice of element set (2 or 3; Note 1)
DATE0Ddate of osculation (TT MJD) for the given
elements
DATE1Ddate of osculation (TT MJD) for the updated
elements
+

+
GIVEN (the unperturbed elements): +
+
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
EPOCH0Depoch of the given element set +(t0 or T, TT MJD;
Note 2)
ORBI0Dinclination (i, radians)
ANODE0Dlongitude of the ascending node ($\Omega$, radians)
PERIH0Dargument of perihelion +($\omega$, radians)
AORQ0Dmean distance or perihelion distance (a or q, AU)
E0Deccentricity (e)
AM0Dmean anomaly (M, radians, JFORM=2 only)
+

+
RETURNED (the updated elements): +
+
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
EPOCH1Depoch of the updated element set +(t0 or T,
TT MJD; Note 2)
ORBI1Dinclination (i, radians)
ANODE1Dlongitude of the ascending node ($\Omega$, radians)
PERIH1Dargument of perihelion +($\omega$, radians)
AORQ1Dmean distance or perihelion distance (a or q, AU)
E1Deccentricity (e)
AM1Dmean anomaly (M, radians, JFORM=2 only)
+

+
RETURNED (status flag): +
+
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
JSTATIstatus:
+102 = warning, distant epoch
+101 = warning, large timespan +(>100 years)
+1 to +8 = coincident with major planet +(Note 6)
0 = OK
-1 = illegal JFORM
-2 = illegal E0
-3 = illegal AORQ0
-4 = internal error
-5 = numerical error
+

+
NOTES: +
+
1. +
Two different element-format options are supported, as follows.
+JFORM=2, suitable for minor planets: +

+ 		 EPOCH 		 = 		 epoch of elements t0 (TT MJD)
+		 ORBINC 		 = 		 inclination i (radians)
+		 ANODE 		 = 		 longitude of the ascending node $\Omega$ (radians)
+		 PERIH 		 = 		 argument of perihelion $\omega$ (radians)
+		 AORQ 		 = 		 mean distance a (AU)
+		 E 		 = 		 eccentricity e $( 0 \leq e < 1 )$ 
+		 AORL 		 = 		 mean anomaly M (radians)        
+
+

+JFORM=3, suitable for comets: +


+ 		 EPOCH 		 = 		 epoch of perihelion T (TT MJD)
+		 ORBINC 		 = 		 inclination i (radians)
+		 ANODE 		 = 		 longitude of the ascending node $\Omega$ (radians)
+		 PERIH 		 = 		 argument of perihelion $\omega$ (radians)
+		 AORQ 		 = 		 perihelion distance q (AU)
+		 E 		 = 		 eccentricity e $( 0 \leq e \leq 10 )$
+
2. +
DATE0, DATE1, EPOCH0 and EPOCH1 are all instants of time in + the TT timescale (formerly Ephemeris Time, ET), expressed + as Modified Julian Dates (JD-2400000.5). +
    +
  • DATE0 is the instant at which the given + (i.e. unperturbed) osculating elements are correct. +
  • DATE1 is the specified instant at which the updated osculating + elements are correct. +
  • EPOCH0 and EPOCH1 will be the same as DATE0 and DATE1 + (respectively) for the JFORM=2 case, normally used for minor + planets. For the JFORM=3 case, the two epochs will refer to + perihelion passage and so will not, in general, be the same as + DATE0 and/or DATE1 though they may be similar to one another. +
+
3. +
The elements are with respect to the J2000 ecliptic and mean equinox. +
4. +
Unused elements (AM0 and AM1 for JFORM=3) are not accessed. +
5. +
See the sla_PERTUE routine for details of the algorithm used. +
6. +
This routine is not intended to be used for major planets, which + is why JFORM=1 is not available and why there is no opportunity + to specify either the longitude of perihelion or the daily + motion. However, if JFORM=2 elements are somehow obtained for a + major planet and supplied to the routine, sensible results will, + in fact, be produced. This happens because the sla_PERTUE routine + that is called to perform the calculations checks the separation + between the body and each of the planets and interprets a + suspiciously small value (0.001 AU) as an attempt to apply it to + the planet concerned. If this condition is detected, the + contribution from that planet is ignored, and the status is set to + the planet number (Mercury=1,...,Neptune=8) as a warning. +
+

+
REFERENCE: +
Sterne, Theodore E., An Introduction to Celestial Mechanics, +Interscience Publishers, 1960. Section 6.7, p199. +
+
+ +next + +up + +previous +
+ Next: SLA_PERTUE - Perturbed Universal Elements +
+Up: SUBPROGRAM SPECIFICATIONS +
+ Previous: SLA_PERMUT - Next Permutation +

+

+

+SLALIB --- Positional Astronomy Library
Starlink User Note 67
P. T. Wallace
12 October 1999
E-mail:ptw@star.rl.ac.uk +
+ + -- cgit