ut1utc filename
Load an ephemeris of UT1-UTC.
InputFile filename
~mcs/CBI/ephem/ut1utc.ephem
.
ut1utc ~mcs/CBI/ephem/ut1utc.ephem
To track sources precisely the control program needs to be given an ephemeris of UT1-UTC.
#
character and extend to the end of the line.
# CBI Ephemeris of UT1-UTC # # Note that MJD = JD - 2400000.5 # # UTC (MJD) UT1-UTC (s) Calendar (UTC) #---------- ----------- -------------- 50842.00000 +0.169790 # 1998-Jan-29 50843.00000 +0.167580 # 1998-Jan-30 50844.00000 +0.165260 # 1998-Jan-31 50845.00000 +0.162890 # 1998-Feb-01 50846.00000 +0.160560 # 1998-Feb-02 50847.00000 +0.158320 # 1998-Feb-03The current ephemeris was produced by visiting:
ftp://maia.usno.navy.mil/ser7/ser7.datwith Netscape, using cut and paste to copy the body of the primary table to a text file, then applying the following awk script to the result.
#!/bin/awk -f BEGIN { # When the expected column headings of the table have been seen, in_table # will be set to 1. in_table = 0 # Create a lookup table of 3-letter month names. split("Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec", months) } # In the current bulletin there are four column headings. The first # three columns don't have names. Once these headings have been seen # the file header has passed and the table of data should start. $1=="MJD" && $2=="x(arcsec)" && $3=="y(arcsec)" && $4=="UT1-UTC(sec)" { in_table = 1; # Describe the contents of the ut1-utc ephemeris that is being produced. printf("# CBI Ephemeris of UT1-UTC\n"); printf("#\n"); printf("# Note that MJD = JD - 2400000.5\n"); printf("#\n"); printf("# UTC (MJD) UT1-UTC (s) Calendar (UTC)\n"); printf("#---------- ----------- --------------\n"); } # The current bulletin has 7 columns, which are: # year, month(1-12), day(1-31), MJD x(arcsec) y(arcsec) UT1-UTC(sec). in_table!=0 && NF==7 && $1 ~ /^(19|20)[0-9][0-9]/ { year = $1; month = months[$2]; day = $3; mjd = $4; ut1utc = $7; printf("%.5f %+10.6f # %s-%s-%02d\n", mjd, ut1utc, year, month, day); }