Instructions:
Download python:
https://www.python.org/downloads/
Open a new file in IDLE
Copy and paste the code into the window
Hit f5
It will ask you to save it. Give it a filename
It will give a perpetual calendar so you can always get GHA and SHA. This is the first step.
It was one of my first python programmes, so the code is pretty hairy. It works for the Sun well, but for some reasons there seem to be some errors when I compare to professional tables. I don't think it will give much error, but it is a start at least.