Index
Date rise_date(source, utc, horizon)
Return the nearest date and time at which a given source rises.
- Arguments:
-
Source source
- The source to describe.
Date utc
- The date and time around which to search for the rise time.
Elevation horizon
- The elevation of the local horizon to be used when
calculating the rise time.
Example:
The following example displays the date and time at which Jupiter
will rise or did rise above 43 degrees. If Jupiter doesn't rise
for more than 12 hours, the previous rise time is shown. If
Jupiter doesn't rise at all, the zero point of Modified Julian
Date (17-Nov-1858) is displayed.
print $rise_date(jupiter,$date(),43)
Example:
The following examples is used to stop observing 15 minutes
before the sun rises above the -2 degree horizon.
Date stop_time = $rise_date(sun,$date,-2) - 15m
catch $date >= $stop_time {
...observe while the sun is safely below the horizon...
} {
print "The sun is about to rise."
exit
}
Martin Shepherd (21-Aug-2000)