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diff --git a/noao/astutil/doc/asttimes.hlp b/noao/astutil/doc/asttimes.hlp new file mode 100644 index 00000000..eefc17df --- /dev/null +++ b/noao/astutil/doc/asttimes.hlp @@ -0,0 +1,128 @@ +.help asttimes May93 astutil +.ih +NAME +asttimes -- Compute UT, Julian day, epoch, and sidereal time +.ih +USAGE +asttimes +.ih +PARAMETERS +.ls files = "" +List of files containing local dates and times for which the astronomical +dates and times are desired. If no input files are specified then task +parameters are used. +.le +.ls header = yes +Print header and observatory information to output? +.le +.ls observatory = ")_.observatory" +Observatory for which times are to be computed. The default is a +redirection to look in the parameters for the parent package for a value. +The final value of this parameter may be one of the +observatories in the observatory database, "observatory" to select the +observatory defined by the environment variable "observatory" or the +parameter \fBobservatory.observatory\fR, or "obspars" to select the +current parameters set in the \fBobservatory\fR task. See help for +\fBobservatory\fR for additional information. +.le +.ls year, month, day, time +If no input files are specified then the date and time for which the +astronomical date and time is computed are given by these parameters. +If the year is less than 100 then the century is assumed to be 1900. +The month is specified as an integer between 1 and 12, and the local +time for the specified time zone is in hours (sexagesimal format is +acceptable). +.le +.ls ut, epoch, jd, lmst +If no input files are specified then the universal time, J2000 Julian epoch, +Julian day, and local mean sidereal time (at the specified longitude) +are recorded in these parameters for possible reference as CL +variables. This is in addition to the usual printed output. +.le +.ih +DESCRIPTION +The astronomical quantities of universal time, J2000 Julian epoch, Julian day, +and local mean sidereal time at the specified observatory are computed and +printed for the given dates and times. To compute parameters for a +location not specified in the observatory database use the observatory name +"obspars" which will use the values defined by the parameters +\fIobservatory.longitude\fR and \fIobservatory.timezone\fR. The input +dates and times may be taken from files containing the year, month (as an +integer between 1 and 12), day, and local time (sexagesimal notation is +acceptable) in the specified time zone. If no files are specified then task +parameters are used. The output consists of a printed table with optional +header and the input data and derived astronomical data. In addition, if +the input date and time is from the task parameters then the astronomical +times are recorded in the user's parameter file (provided the task is not +run as a background job). These parameters may then be used as CL +parameters. +.ih +EXAMPLES +1. For use directly without data files set the date and time using +the parameter editor, with explicit assignments, or on the command line: + +.nf + cl> asttimes year=1987 month=10 day=28 time=15:30 obs=kpno + # ASTTIMES: Observatory parameters for Kitt Peak National Observatory + # timezone = 7 + # longitude = 111:36.0 + ##YR MON DAY ZT UT EPOCH JD LMST + 1987 10 28 WED 15:30:00.0 22:30:00.0 1987.82324 2447097.4375 17:30:31.8 + cl> =asttimes.lmst + 17.508823973881 +.fi + +2. To make a table using a CL loop: + +.nf + cl> asttimes.observatory="kpno" + cl> asttimes.year=1987 + cl> asttimes.month=10 + cl> asttimes.time=0 + cl> for (i=10; i<16; i+=1) { + >>> asttimes (day=i, header=no) + >>> } + 1987 10 10 SAT 0:00:00.0 7:00:00.0 1987.77219 2447078.7917 0:47:01.0 + 1987 10 11 SUN 0:00:00.0 7:00:00.0 1987.77493 2447079.7917 0:50:57.5 + 1987 10 12 MON 0:00:00.0 7:00:00.0 1987.77766 2447080.7917 0:54:54.1 + 1987 10 13 TUE 0:00:00.0 7:00:00.0 1987.78040 2447081.7917 0:58:50.7 + 1987 10 14 WED 0:00:00.0 7:00:00.0 1987.78314 2447082.7917 1:02:47.2 + 1987 10 15 THU 0:00:00.0 7:00:00.0 1987.78588 2447083.7917 1:06:43.8 +.fi + +In practice the output would be directed to a file: + + >>> asttimes (day=i, header=no, >>"table") + +3. To use an input file: + +.nf + cl> asttimes f=dates > table + cl> type table + # ASTTIMES: Observatory parameters for Kitt Peak National Observatory + # timezone = 7 + # longitude = 111:36.0 + ##YR MON DAY ZT UT EPOCH JD LMST + 1987 10 28 WED 22:00:00.0 5:00:00.0 1987.82398 2447097.7083 0:01:35.8 + 1987 10 28 WED 23:00:00.0 6:00:00.0 1987.82409 2447097.7500 1:01:45.7 + 1987 10 29 THU 0:00:00.0 7:00:00.0 1987.82421 2447097.7917 2:01:55.5 + 1987 10 29 THU 1:00:00.0 8:00:00.0 1987.82432 2447097.8333 3:02:05.4 +.fi +.ih +REVISIONS +.ls ASTTIMES V2.10.3 +The epoch was changed from day of the year divided by 365.25 to the +precise J2000 Julian epoch definition. In addition to changing +the output value this fixes incorrect values JD and LMST around the +new year. + +The times are now always printed in the proper 24 hour interval instead +of using negative or values greater than 24 to indicate the day difference +with Greenwich. + +The header parameter now suppress printing the observatory information. +.le +.ih +SEE ALSO +observatory +.endhelp |