catalog filename
Load sources from a source catalog file.
InputFile filename
~mcs/ovro/ephem/source.cat
to the current source
catalog. New sources with the same names as ones that are
already in the catalog replace the old ones.
catalog ~mcs/ovro/ephem/source.cat
#
character and extend to the end of the line. The following
example would be valid as a source catalog, and shows examples of
all the supported syntax:
# This is a comment. #----------------------------------------------------------------------- # The following entry describes a source called "alyr" by its # J2000 Right Ascension, Declination, and its J2000 proper motion # per Julian year in Right Ascension and Declination. # # Source Equatorial position Proper motion/yr # RA Dec RA Dec # type name hh:mm:ss.sss dd:mm:ss.ss h:m:ss.ssss d:m:ss.sss #----------------------------------------------------------------------- J2000 alyr 18:35:14.655 38:44:09.68 +0:0:00.0170 +0:0:00.285 #----------------------------------------------------------------------- # The following entry describes a J2000 source with no proper motion. # # Source Equatorial position # RA Dec # type name hh:mm:ss.sss dd:mm:ss.ss #----------------------------------------------------------------------- J2000 0003-066 00:03:40.290 -06:40:17.60 #----------------------------------------------------------------------- # The following entry defines "vega" as an alternate name for "alyr". # # type name existing name #----------------------------------------------------------------------- alias vega alyr #----------------------------------------------------------------------- # The following entry defines the local zenith in terms of fixed # telescope axis positions. # # type name azimuth elevation #----------------------------------------------------------------------- fixed zenith 0 90.0 #----------------------------------------------------------------------- # The following entry defines the sun as a source who's equatorial # position is defined by the contents of an ephemeris file. # # type name ephemeris-file #----------------------------------------------------------------------- ephem sun ~mcs/ovro/ephem/sun.ephem #----------------------------------------------------------------------- # The following defines an example source called south45geoc that has # a fixed geocentric azimuth and elevation. When this source is # passed to the track command, the telescope actively tracks this # geocentric position, dynamically taking into account of the # time-varying effects of changing atmospheric refraction in the # conversion to topocentric coordinates, responding to any changes # that the schedule or the observer makes to the X, Y, az, or el # pointing offsets, accomodating any changes that are made to the # pointing model parameters, and dynamically correcting for the # time-varying azimuth tilt-meter readings. #----------------------------------------------------------------------- horiz south45geoc geoc 180 45.0 #----------------------------------------------------------------------- # The following defines an example source called south45topo that has # a fixed topocentric azimuth and elevation. When this source is # passed to the track command, the telescope actively tracks this # topocentric position, dynamically responding to any changes that # the schedule or the observer makes to the X, Y, az, or el pointing # offsets, accomodating any changes that are made to the pointing # model parameters, and dynamically correcting for the time-varying # azimuth tilt-meter readings. #----------------------------------------------------------------------- horiz south45topo topo 180 45.0 #----------------------------------------------------------------------- # The following defines an example source called south45mount that # has a fixed mount azimuth and elevation. When this source is passed # to the track command, the telescope actively tracks this mount # position, dynamically responding to any changes that the schedule # or the observer makes to the X, Y, az, or el pointing offsets. # # Note that this differs from a FIXED source definition, since # tracking a fixed source tells the telescope to just slew to the # specified mount az,el position and halt there, without heeding any # pointing offsets. #----------------------------------------------------------------------- horiz south45mount mount 180 45.0
#----------------------------------------------------------------------- # Ovro 40m Ephemeris for Mars # # Note that TT ~= TAI + 32.184. # See slaDtt.c for how to convert TT to UTC. # # Also note that MJD = JD - 2400000.5 # # MJD (TT) Right Ascen Declination Distance (au) Calendar (TT) #--------- ------------- ------------- ------------ ----------------- 50814.0000 20:54:12.9302 -18:39:22.171 2.1366386049 # 1998-Jan-01 00:00 50815.0000 20:57:24.0642 -18:26:03.652 2.1398752328 # 1998-Jan-02 00:00 50816.0000 21:00:34.7660 -18:12:33.346 2.1431046252 # 1998-Jan-03 00:00 50817.0000 21:03:45.0305 -17:58:51.438 2.1463269705 # 1998-Jan-04 00:00Note that comments are introduced with the '
#
' character
and they extend to the end of the containing line.
The OVRO 40m ephemerides were produced as follows. JPL provides an
E-mail service for generating ephemerides. For each source of interest
one submits a batch-job file via E-mail and a few minutes later
receives one or more automated replies containing the requested
ephemeris entries. One then has to remove the E-mail headers, splice
the E-mails together in the correct order and then apply the following
awk script to the result to produce the OVRO 40m ephemeris of the
source. Note that the comments in the header of the script also
outline the details of the batch file and its submittal.
#!/usr/bin/awk -f #----------------------------------------------------------------------- # Convert the format of an E-mailed JPL ephemeris to a machine readable # form. To have a new ephemeris sent by JPL, change the COMMAND, START_TIME, # STOP_TIME and STEP_SIZE parameters of the following, remove the initial # # characters and E-mail the result to horizons@ssd.jpl.nasa.gov, along # with the subject line: JOB-SUBMITTAL # #!$$SOF (ssd) JPL/Horizons Execution Control VARLIST July, 1997 # EMAIL_ADDR = mcs@astro.caltech.edu # COMMAND = 'mars' # OBJ_DATA = NO # MAKE_EPHEM = YES # TABLE_TYPE = OBS # CENTER = GEO # COORD_TYPE = GEODETIC # SITE_COORD = '0,0,0' # START_TIME = '1997-JAN-1 00:00' # STOP_TIME = '1998-JAN-1 00:00' # STEP_SIZE = '1 days' # QUANTITIES = '2,20' # REF_SYSTEM = J2000 # CAL_FORMAT = BOTH # ANG_FORMAT = HMS # APPARENT = AIRLESS # TIME_TYPE = TT # ELEV_CUT = -90 # SKIP_DAYLT = NO # AIRMASS = 38.D0 # EXTRA_PREC = YES # CSV_FORMAT = NO #!$$EOF+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ # #----------------------------------------------------------------------- # The following variable will be 1 until the start of the ephemeris # is seen. This allows for rejection of lines of the header section # that might otherwise be interpreted as ephemeris entries. BEGIN { in_header=1 } # Get the name of the target planet from the header. /^Target body/ { printf("# OVRO 40m Ephemeris for %s\n", $4); } # The following pattern matches the start of the ephemeris table. /^\$\$SOE/ { # Signal that we have finished reading the header section. in_header=0; # Describe the contents of the file. printf("#\n"); printf("# Note that TT ~= TAI + 32.184.\n"); printf("# See slaDtt.c for how to convert TT to UTC.\n"); printf("#\n"); printf("# Also note that MJD = JD - 2400000.5\n"); printf("#\n"); printf("# MJD (TT) Right Ascen Declination Distance (au) Calendar (TT)\n"); printf("#--------- ------------- ------------- ------------ -----------------\n"); } # Output reformatted ephemeris lines. /^ [0-9]/ && !in_header { printf("%.4f %s:%s:%s %s:%s:%s %s # %s %s\n", $3 - 2400000.5, $4,$5,$6, $7,$8,$9, $10, $1, $2); } # The job is complete when the end of the ephemeris table is reached. /^\$\$EOE/ { exit }For the standard solar system objects I used that the following values for the COMMAND and STEP_SIZE parameters.
COMMAND STEP_SIZE Sun 'sun' '1 days' Mercury 'mercury' '12 hours' Venus 'venus' '1 days' Moon '301' '6 hours' Mars 'mars' '1 days' Jupiter Barycenter '599' '1 days' Saturn Barycenter '699' '1 days' Uranus Barycenter '799' '1 days' Neptune Barycenter '899' '1 days' Pluto Barycenter '999' '1 days'Note that JPL says that the batch program may change over time, so be prepared for the above procedures to need some adjustments. The example batch file that they provided me with listed the following options for requesting up to date information about their "Horizons" facility. Simply send an empty E-mail to horizons@ssd.jpl.nasa.gov with one of the following subjects:
HORIZONS-BATCH-LONG (Request latest fully commented example batch file) HORIZONS-BATCH-BRIEF (Request latest example batch file without comments) HORIZONS-DOC-TEXT (Request ASCII version of current documentation) HORIZONS-DOC-PS (Request PostScript version of current documentation) HORIZONS-QUESTION (Message fowarded to cognizant engineer)You can also invoke an interactive session by typing:
telnet ssd.jpl.nasa.gov 6775Or by accessing http://ssd.jpl.nasa.gov/cgi-bin/eph with a Web browser.