There are some handy utils for un*x systems that can do the task of calculating sunrise/sunset/civil twilight/etc times given a latitude and longitude input.  Unfortunately I was not able to locate any win32 console apps that can do this reliably.   I found one written by an author who is no longer reachable and his contains a daylight-savings bug (DST calculation doesn't seem to work).  Daylight savings is a very important and tricky factor.

The reason I would like to have such a program is to use it in batch files to schedule home automation tasks such as turning out outside lights, controlling thermostat settings etc, based on sunrise/sunset/twilight times which change each day.

As a starting point you might consider the following URLs for assistance with the algorithms:

http://www.codeproject.com/datetime/srss.asp

http://www.freevbcode.com/ShowCode.asp?ID=341

http://xoomer.virgilio.it/vtomezzo/sunriset/formulas/index.html

there are others but that is a start...

will anyone be so kind as to create this program?? ;)  all it needs to do is output the time in 24hour hh:mm format, no fancy GUI is needed (at least for me!).  It would be good if it can accept some commandline arguments such as specifying a date manually (default would be todays date) and also the ability to output only the time you need for example just the SUNRISE time.

example:

>suntime.exe 40.734N 73.986W -time sunrise
05:39

>suntime.exe 40.734N 73.986W -time sunset
17:33

>suntime.exe 40.734N 73.986W -time twilight
16:55

etc etc...
 :Thmbsup: