Computing dates when an LST is at night time

The program nighttime (written by Mike Nolan and available on AO computers - e.g., mofongo.naic.edu) computes the dates when a particular LST occurs at night time at Arecibo. The Start LST and End LST inputs for the program are in the format hhmm or hh:mm and the Start date is in the format yyyy-mm-dd. If the start date is not given, today's date is assumed. By default, number of days is the number of days of a year.

Some examples:

nighttime 0500 0700 2012-09-01
and the output would be
Day 2012-09-01
Night 2012-10-08
Day 2013-03-04
nighttime 0500 0700 2012-09-01 1000
and the output would be
Day 2012-09-01
Night 2012-10-08
Day 2013-03-04
Night 2013-10-08
Day 2014-03-04
Night 2014-03-19
Day 2014-03-20
Night 2014-10-09
Day 2015-03-04

The nighttime program prints out the word "Night" on the first date when the LSTs fall entirely at night, and "Day" on the first date when the LSTs sometimes cross into daytime. (Rise/Set is defined to be when the center of the sun is 0.833 degrees below the horizon.)

Page last modified by Gomathi (gomathi@naic.edu)