sunwait is a [very] old and simple application for calculating sun rise & set times for a given location. It is designed to be used with cron but can be used as a standalone application. There are newer versions around, but these instructions refer to the original, last updated in 2004 version.

There are various instructions on how to install it on a raspberrypi, I struggled to find all the stages in one place, so through it would be helpful to list them [ thanks to carrotjuice , B.Goode and scruss for the source information ] – link to relevant Pi forum .

tar xvzf sunwait-20041208.tar.gz
cd sunwait-20041208/
sudo cp sunwait /usr/local/bin

You can then check it is installed ok with

sunwait -p

To run it for your location add the relevant lat and lon as shown below;

sunwait -p 51.4826N 0W

This is roughly the position of the Greenwich Meridian line in London giving the following output


You can find some simple code on my git hub in the RC-433 stuff folder to see how I extract the sunrise / set time within a Python application [ look for ], it is a little crude but seems to work reliably.