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NAME:
JD_SYNC
PURPOSE:
CATEGORY:
CALLING SEQUENCE:
subroutine JD_SYNC(IJD,EARTH,bForeCast,XCbeg,XCtst,JDref,JDcntr,XCEarth,LatEarth,nCar,JDCar)
INPUTS:
OUTPUTS:
CALLS: ***
ECLIPTIC_HELIOGRAPHIC, FLINT8, Julian, SunNewcomb, XMAP_SC_POS
INCLUDE:
include 'sun.h'
EXTERNAL:
external EARTH
PROCEDURE:
MODIFICATION HISTORY:
JUN-1995, Paul Hick (UCSD)
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NAME:
jpl_close
PURPOSE:
Closes ephemeris file
CALLING SEQUENCE:
entry jpl_close()
CALLS: ***
CvI4, CvR8, Say, bOSFindClose, bOpenFile, iFilePath, iFreeLun, iSearch, jpl_inside
jpl_interp
PROCEDURE:
Read explanation in jpl_eph2. Currently this function is useless.
MODIFICATION HISTORY:
FEB-2005, Paul Hick (UCSD/CASS; pphick@ucsd.edu)
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NAME:
jpl_eph
PURPOSE:
Read the JPL planetary ephemeris and gives position and velocity
of body 'ntarg' with respect to body 'ncent'.
CATEGORY:
gen/for/lib
CALLING SEQUENCE:
logical function jpl_eph(jd,ntarg,ncent,rrd,bKm,bBary)
INPUTS:
jd double precision Ephemeris time specified as Julian day.
For other input arguments (ntarg, ncent, bKm and bBary)
see jpl_eph2.
OUTPUTS:
rrd(6) double precision position vector (see jpl_eph)
jpl_eph logical status indicator (see jpl_eph)
CALLS: ***
jpl_eph2
CALLED BY:
jpl_test
EXAMPLE:
logical bOK
logical jpl_eph
double precision jd
double precision rrd(6)
ncent = 3 ! Earth at origin
ntarg = 10 ! Moon
bOK = jpl_eph(jd,ntarg,ncent,rrd,.FALSE.,.FALSE.)
! The ephemeris fails only if the JPL ephemeris files are not
! found (probably means environment variable $EPHEM is not defined),
! or if the input jd is earlier than 1950 or later than 2050 (probably
! means jd was calculated wrong).
if ( .not. bOK ) stop 'bad ephemeris'
! Switch to single precision
x = rrd(1)
y = rrd(2)
z = rrd(3)
! RA, dec in degrees
ra = atan2d( y, x )
dec = atan2d( z, sqrt( x*x+y*y ) )
PROCEDURE:
See jpl_eph2 for full documentation.
jpl_eph is just a wrapper for jpl_eph2.
The only difference is in the first argument (the time).
MODIFICATION HISTORY:
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NAME:
jpl_eph2
PURPOSE:
Read the JPL planetary ephemeris and gives position and velocity
of body 'ntarg' with respect to body 'ncent'.
CATEGORY:
gen/for/lib
CALLING SEQUENCE:
logical function jpl_eph2(et,ntarg_,ncent_,rrd,bKm,bBary)
INPUTS:
et(2) double precision Ephemeris time specified as Julian day.
A. put entire epoch in et(1) and set et(2)=0 (equivalent to jpl_eph)
B. for maximum interpolatin accuracy, set et(1) to the most recent midnight
at or before the interpolation time, and put the remaining fraction in et(2)
C. pick a fixed epoch for et(1) and put the elapsed time since that
epoch in et(2)
ntarg integer number of the body whose position and velocity are needed
ncent integer number of the body used as the origin
The numbering convention for NTARG and NCENT is:
0 = SUN (same as 11)
1 = MERCURY 9 = PLUTO
2 = VENUS 10 = MOON
3 = EARTH 11 = SUN
4 = MARS 12 = NUTATIONS (LONGITUDE AND OBLIQ)
5 = JUPITER 13 = LIBRATIONS, IF ON EPH FILE
6 = SATURN 14 = SOLAR-SYSTEM BARYCENTER
7 = URANUS 15 = EARTH-MOON BARYCENTER
8 = NEPTUNE
(For nutations and librations used NTARG=12 and 13 respectively. NCENT is ignored)
bKm logical flag setting the units of the output (default: .FALSE.)
bKm = .TRUE. : KM and KM/SEC
= .FALSE.: AU and AU/DAY
bKm determines the time unit for nutations and librations
The angles are always in radians.
bBary logical flag defining the output center (default: .FALSE.)
(affects only the 9 planets)
bBary = .TRUE. : center is solar system barycenter
= .FALSE.: center is Sun
OUTPUTS:
rrd(6) double precision
Position (AU or km) and velocity (AU/day or km/s) of NTARG with
respect to NCENT
For librations the units are radians and radians/day
For nutations the first four will be set (units of radians and
radians/day).
jpl_eph2 logical return value of call to jpl_init.
will be .FALSE. if input time was outside range of ephemeris
file or if there was a read error. Otherwise .TRUE.
CALLS: ***
ArrI4Zero, ArrR8Copy, ArrR8Zero, jpl_init, jpl_message, jpl_split, jpl_state
CALLED BY:
Time2jpl_eph, jpl_eph
RESTRICTIONS:
The ephemeris files are organized in records covering periods of 32 days.
When the ephemeris is accessed for a large number of times inside a time
range less than 32 days, the ephemeris file is accessed only once or twice,
reading in 32-days worth of data.
In this case it may be advantageous to close the ephemeris file
explicitly using jpl_close after each jpl_eph2 call. jpl_state will work
with the data in memory until a time outside the 32-day range is requested.
If this happens the appropriate ephemeris file is opened, and the required
record is read. This way the ephemeris file is open only for those brief
moments when a new 32-day period is needed. The disadvantage is a speed
penalty incurred because of repeated opening of files.
NOTE: currently the ephemeris file is closed after a record is read,
so a call to jpl_close is not needed. To keep the ephemeris file open
the call to iFreeLun in jpl_state needs to be commented out.
PROCEDURE:
Currently two ephemeris files are accessed: 1950-2000 and 2000-2050.
MODIFICATION HISTORY:
????, Paul Hick (UCSD/CASS)
Based on original JPL package. See:
ftp://ssd.jpl.nasa.gov/pub/eph/planets/fortran/
FEB-2005, Paul Hick (UCSD/CASS; pphick@ucsd.edu)
Allow 0 to represent Sun (in addition to 11)
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NAME:
jpl_init
PURPOSE:
Initializes the JPL planetary ephemeris and opens an ephemeris file
(internal use by jpl_eph2 only)
CALLING SEQUENCE:
entry jpl_init(et,bOK)
INPUTS:
et(2) double precision ephemeris time
OUTPUTS:
bOK logical .TRUE.: ephemeris data available
(it is OK to call jpl_state)
.FALSE.: no ephemeris available.
(do not bother to call jpl_state)
CALLED BY:
jpl_eph2
SIDE EFFECTS:
The variable NR (record for time et) is set here and will be used by jpl_state.
The ephemeris file DOES NOT need to be open. As long as the record
still in memory matches NR, jpl_state has all the information it needs.
CALLS: ***
CvI4, CvR8, Say, bOSFindClose, bOpenFile, iFilePath, iFreeLun, iSearch, jpl_inside
jpl_interp
SEE ALSO:
jpl_interp, jpl_split, jpl_state
PROCEDURE:
Entry point in jpl_state
The ephemeris files are located in $EPHEM/jpl
iRecl = 1*2*NCOEFFS ! Multiplier for recordlength in open statement
if (cOpSys .ne. OS__VMS) iRecl = 4*2*NCOEFFS
open (iU, file=cFile, access='DIRECT', form='UNFORMATTED', recl=iRecl, status='OLD')
MODIFICATION HISTORY:
???-????, Paul Hick (UCSD/CASS)
FEB-2005, Paul Hick (UCSD/CASS; pphick@ucsd.edu)
Substantial rewrite.
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NAME:
jpl_inside
PURPOSE:
Check whether specified time is in ephemeris file
CALLING SEQUENCE:
function jpl_inside(et,SS)
CALLS:
jpl_split
CALLED BY:
jpl_close, jpl_init, jpl_state
PROCEDURE:
MODIFICATION HISTORY:
FEB-2005, Paul Hick (UCSD/CASS; pphick@ucsd.edu)
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NAME:
jpl_interp
PURPOSE:
Differentiates and interpolates a set of Chebyshev
coefficients to give position and velocity
CALLING SEQUENCE:
subroutine jpl_interp(BUF,T,NCF,NCM,NA,IFL,pv)
INPUTS:
BUF 1ST LOCATION OF ARRAY OF D.P. CHEBYSHEV COEFFICIENTS OF POSITION
T T(1) IS DP FRACTIONAL TIME IN INTERVAL COVERED BY
COEFFICIENTS AT WHICH INTERPOLATION IS WANTED
(0 .LE. T(1) .LE. 1). T(2) IS DP LENGTH OF WHOLE
INTERVAL IN INPUT TIME UNITS.
NCF # OF COEFFICIENTS PER COMPONENT
NCM # OF COMPONENTS PER SET OF COEFFICIENTS (3 or 2)
NA # OF SETS OF COEFFICIENTS IN FULL ARRAY
(I.E., # OF SUB-INTERVALS IN FULL INTERVAL)
IFL INTEGER FLAG: =1 FOR POSITIONS ONLY
=2 FOR POS AND VEL
OUTPUTS:
pv INTERPOLATED QUANTITIES REQUESTED. DIMENSION
EXPECTED IS pv(NCM,IFL), DP.
CALLED BY:
jpl_close, jpl_init, jpl_state
MODIFICATION HISTORY:
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NAME:
jpl_message
CALLING SEQUENCE:
subroutine jpl_message(cSay,et,cStr)
INPUTS:
cSay character*(*) leading string passed to Say
et(2) double precision ephemeris time
cStr character*(*) trailing string passed to Say
CALLS: ***
Say, Time2Day8, Time2JD, cTime2Str
CALLED BY:
jpl_eph2
MODIFICATION HISTORY:
FEB-2005, Paul Hick (UCSD/CASS; pphick@ucsd.edu)
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NAME:
jpl_split
PURPOSE:
Breaks a double precision number into an integer and fractional part
CALLING SEQUENCE:
subroutine jpl_split(TT,FR)
INPUTS:
TT double precision input number
OUTPUTS:
FR(2) double precision output integer and fraction
FR(1): integer part
FR(2): fractional part (always >= 0)
CALLED BY:
jpl_eph2, jpl_inside
MODIFICATION HISTORY:
???-????, Paul Hick (UCSD/CASS; pphick@ucsd.edu)
From original JPL package
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NAME:
jpl_state
PURPOSE:
Reads and interpolates ephemeris
(internal use by jpl_eph2 only)
CATEGORY:
gen/for/lib
CALLING SEQUENCE:
subroutine jpl_state(et,lst,pv,bKm,bBary,EMR,bOK)
INPUTS:
et(2) double precision
Julian ephemeris epoch at which interpolation is wanted.
Any combination et(1)+et(2) insided the time span covered by the file
is allowed:
A. put entire epoch in et(1) and set et(2)=0
B. for maximum interpolatin accuracy, set et(1) to the most recent midnight
before the interpolation time, and put the remaining fraction in et(2)
C. pick a fixed epoch for et(1) and put the elapsed time since that
epoch in et(2)
lst(15) integer
array specifying what interpolation is wanted for each of the bodies
=0, no interpolation
=1, position only
=2, position and velocity
The designation of the astronomical bodies is the same as used for arguments
NTARG and NCENT in jpl_eph
OUTPUTS:
pv(6,15) double precision
array with the interpolated quantities
THE BODY SPECIFIED BY lst(I) WILL HAVE ITS STATE IN THE ARRAY STARTING AT
pv(1,I). (ON ANY GIVEN CALL, ONLY THOSE WORDS IN 'pv' WHICH ARE AFFECTED BY
THE FIRST 10 'lst' ENTRIES (AND BY lst(14) IF LIBRATIONS ARE ON THE FILE)
ARE SET. THE REST OF THE 'pv' ARRAY IS UNTOUCHED.) THE ORDER OF COMPONENTS
STARTING IN pv(1,I) IS: X,Y,Z,DX,DY,DZ.
ALL OUTPUT VECTORS ARE REFERENCED TO THE EARTH MEAN EQUATOR AND EQUINOX OF J2000
IF THE DE NUMBER IS 200 OR GREATER; OF B1950 IF THE DE NUMBER IS LESS THAN 200.
The Moon state is always geocentric. THE OTHER NINE STATES ARE EITHER HELIOCENTRIC
OR SOLAR-SYSTEM BARYCENTRIC, DEPENDING ON THE SETTING OF bBary
pv(6,11)ARRAY CONTAINING THE BARYCENTRIC POSITION AND VELOCITY OF THE SUN.
pv(6,12)NUTATIONS, IF ON FILE, ARE PUT INTO pv(K,12) IF lst(12) IS 1 OR 2.
THE ORDER OF QUANTITIES IN pv IS:
D PSI (NUTATION IN LONGITUDE)
D EPSILON (NUTATION IN OBLIQUITY)
D PSI DOT
D EPSILON DOT
pv(6,13)LUNAR LIBRATIONS, IF ON FILE, ARE PUT INTO pv(K,13) IF lst(13) IS 1 OR 2.
CALLS: ***
CvI4, CvR8, Say, bOSFindClose, bOpenFile, iFilePath, iFreeLun, iSearch, jpl_inside
jpl_interp
CALLED BY:
jpl_eph2
SEE ALSO:
jpl_eph, jpl_init
INCLUDE:
include 'dirspec.h', include 'filparts.h', include 'openfile.h', O-Z)
implicit double precision (A-H
PROCEDURE:
MODIFICATION HISTORY:
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NAME:
jpl_test
PURPOSE:
Test program for JPL ephemeris
CATEGORY:
Ephemeris
CALLING SEQUENCE:
program jpl_test
INPUTS:
(file $sys/jpl/testpo.405)
OUTPUTS:
(none)
INCLUDE:
include 'dirspec.h'
CALLS: ***
iFilePath, iGetLun, jpl_eph
PROCEDURE:
Compares data read from the ephemeris files with
data in the testpo.405 file.
MODIFICATION HISTORY:
JAN-2001, Paul Hick (UCSD; pphick@ucsd.edu)
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NAME:
Julian
PURPOSE:
Of the four quantities, date, Julian day number, Julian and Besselian
epoch, one is supplied. The other three are then calculated.
CATEGORY:
Time keeping
CALLING SEQUENCE:
subroutine Julian(IDIN,iYr,Doy,JDio,JEpoch)
INPUTS:
IDIN integer ID=0 date --> JD, Julian epoch, Besselian epoch
=1 JD --> Date, Julian epoch, Besselian epoch
=2 Julian epoch --> Date, JD, Besselian epoch
(not active) =3 Besselian epoch --> Date, JD, Julian epoch
Add 10: use modified Julian days (=JD-2400000.5)
Add 20: use days relative to Jan. 1, 2000 (=JD-2451544.5)
INPUTS/OUTPUTS: (depending on value of ID)
iYr integer year; the year xxxBC should be entered as -xxx+1.
Doy real day of year (including fraction for the time of day).
JD double precision Julian day
JEpoch double precision Julian epoch = time in Julian years
CALLED BY:
AdjustJDCar, BList_NSO_NOAA, BList_WSO_NOAA, ECLIPTIC_EQUATOR
ECLIPTIC_HELIOGRAPHIC, ExtractInsitu, GIPSCAST, GIPSIMP, HERDISK, HOSOrbit, JD_SYNC
MAP_CarrTime, MAP_TZERO, MKVTRACE, MessengerOrbit, N_CARRINGTON, Pandora
PlanetOrbit, READ_HOS, ReadG, ReadGHD, ReadVIPS, ReadVIPSLOSCheck, ReadVIPSLOSCheckn
ReadVIPSn, SetGrid, StereoAOrbit, StereoBOrbit, StereoOrbit, SunNewcomb
UlyssesOrbit, Write3D_bb_UT, Write3D_nv_UT, XMAP_SC_POS, ipsd, ipsdt, sim_MOD
PROCEDURE:
Dates before 5 october 1582 are interpreted as Julian dates;
after 15 october as Gregorian dates.
5 october 1582 (Julian) = 15 october 1582 (Gregorian).
RJD 'relative' Julian day = (Julian day - 2451544.5)
J2000.0 = 2000 January 1.5d TDB = JD 2451545.0
JD 2451544.5 = 2000 January 1.0d (i.e. 1 January, midnight)
Check: JD 2398220.0 = 1854 Jan. 1.5d
JD 2299161.0 = 1582 Oct. 15.5d (Gregorian calender)
= 1582 Oct. 5.5d (Julian calender)
(Doy = 278.5)
JD 0.0 = -4712 Jan. 1.5d
JEpoch 1900 = JD 2415020.0 = Jan 0.5 1900
JEpoch 2000 = JD 2451545.0 = Jan 1.5 2000
MODIFICATION HISTORY:
1989-1990, Paul Hick (MPAE,UCSD/CASS; pphick@ucsd.edu)
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NAME:
Julian8
PURPOSE:
Of the four quantities, date, Julian day number, Julian and Besselian
epoch, one is supplied. The other three are then calculated.
CATEGORY:
Time keeping
CALLING SEQUENCE:
subroutine Julian8(IDIN,iYr,Doy8,JDio,JEpoch)
INPUTS:
IDIN integer ID=0 date --> JD, Julian epoch, Besselian epoch
=1 JD --> Date, Julian epoch, Besselian epoch
=2 Julian epoch --> Date, JD, Besselian epoch
(not active) =3 Besselian epoch --> Date, JD, Julian epoch
Add 10: use modified Julian days (=JD-2400000.5)
Add 20: use days relative to Jan. 1, 2000 (=JD-2451544.5)
INPUTS/OUTPUTS: (depending on value of ID)
iYr integer year; the year xxxBC should be entered as -xxx+1.
Doy8 double precision day of year (including fraction for the time of day).
JD double precision Julian day
JEpoch double precision Julian epoch = time in Julian years
CALLED BY:
ECLIPTIC_HELIOGRAPHIC8, Extractd, Extractd3d, MkTimes, SunNewcomb8, XMAP_SC_POS8
PROCEDURE:
Dates before 5 october 1582 are interpreted as Julian dates;
after 15 october as Gregorian dates.
5 october 1582 (Julian) = 15 october 1582 (Gregorian).
RJD 'relative' Julian day = (Julian day - 2451544.5)
J2000.0 = 2000 January 1.5d TDB = JD 2451545.0
JD 2451544.5 = 2000 January 1.0d (i.e. 1 January, midnight)
Check: JD 2398220.0 = 1854 Jan. 1.5d
JD 2299161.0 = 1582 Oct. 15.5d (Gregorian calender)
= 1582 Oct. 5.5d (Julian calender)
(Doy8 = 278.5)
JD 0.0 = -4712 Jan. 1.5d
JEpoch 1900 = JD 2415020.0 = Jan 0.5 1900
JEpoch 2000 = JD 2451545.0 = Jan 1.5 2000
MODIFICATION HISTORY:
1989-1990, Paul Hick (MPAE,UCSD/CASS; pphick@ucsd.edu)
