NAME

calc_bary -- calculates the barycenter corrections for the orbit data

USAGE

calc_bary input_table output_table RA DEC

DESCRIPTION

calc_bary calculates the barycenter corrections for the ephemeris data and produces a table of corrected orbit times. The input table file should contain all of the split orbit data from multiple observations in a single table.

It has been found that duplicate records sometimes appear in the ephemeris file. If duplicate records are detected, the record is only written once to the correction table and a message is displayed.

The split orbit table file is produced by the task RFITS2PROS . The table is labelled with a "_eph.tab" extension.

The output table contains four columns:

	1) integer part of uncorrected orbit time UT time
	2) real part of uncorrected orbit time in UT time
	3) integer part of corrected orbit time UT time
	4) real part of corrected orbit time in UT time

NOTE: calc_bary MUST be run before apply_bary

PARAMETERS

split_orb = "" prompt = input split orbit table filename

The input split orbit table file name.

orb_corr = "" prompt = output correction table filename

The output table that will be used by the task calc_bary

st_alp = "" prompt = input RA (hh:mm:ss.s)

The RA of the source.

st_dec = "" prompt = input DEC (dd:mm:ss.s)

The DEC of the source.

(ephem_fname = "xtimingdata$de200.tab") [string]

The table name containing the ephemeris date for the barycenter corrections.

(day_col = "MJD_INT") [string]

The date column name of the input table.

(sec_col = "MJD_FRAC") [string]

The seconds column name of the input table.

(xsat_col = "SAT_X") [string]

The x-position of the satellite column name of the input table.

(ysat_col = "SAT_Y") [string]

The y-position of the satellite column name of the input table.

(zsat_col = "SAT_Z") [string]

The z-position of the satellite column name of the input table.

(clobber = no) [boolean]

Boolean flag specifying whether or not the qpoe file can be overwritten, if it already exists.

(display = 1) [int]

The display level. A display level of 0 generates no display. A display level of 1 generates a display of header information.

EXAMPLES

1. Compute the correction table from ephemeris data. Though the user does not have to know this explicitly, you will notice that the input file is in pre-rdf format. The file is first converted to RDF format, a new file (us_ephem.tab) is created, and then the correction table (us_cor.tab) is computed from this intermediate table.

cl> xray
xr> xtiming
xt> timcor
ti> calc_bary
input ephemeris table: ../usarlac_eph.tab
output correction root (_cor.tab): us
input RA (hh:mm:ss.s): 22:07:16.8
input DEC (dd:mm:ss.s): 45:42:0.0

Converting Rev0 US format EPH file to RDF format ...
Opening file: ../usarlac_eph.tab
40 rows written to output table.
Wrote to file: us_ephem.tab

Computing Correction table ...
Opening file: us_ephem.tab
Wrote to Correction table: us_cor.tab

2. Compute correction table from ephemeris data. Though the user does not have to know this explicitly, you will notice that the input file is in RDF format. No file conversion is performed before the correction table in computed.

ti> calc_bary
input ephemeris table: ../rdfarlac_eph.tab
output correction root (_cor.tab): rdf
input RA (hh:mm:ss.s): 22:07:16.8
input DEC (dd:mm:ss.s): 45:42:0.0

RDF input ... No conversion!!

Computing Correction table ...
Opening file: ../rdfarlac_eph.tab
Wrote to Correction table: rdf_cor.tab

TIME REQUIREMENTS

BUGS

SEE ALSO

Documentation on the apply barycenter task (help apply_bary ) for more information on the barycenter routines