For a number of years, I adjusted the timer on my decorative night-lights to turn the lights on and off at different times throughout the year due to the location of Long Beach, California, USA on Earth, the city where I live.  I wanted to build a device that would calculate the time to turn my night-lights on and off automatically by considering parameters such as latitude and longitude and azimuth.  When I learned about the Raspberry Pi computer and discovered its operating system was UNIX based, I knew I could finally build this device.  Just click on the link and the file will download to your computer’s desktop.