Thank you. I must admit that I created the horizon capture because my back yard has the same problem. I thought I was a genius for coming up with the idea, until I did a bit more research and saw that pretty much every astronomy app already have similar functions.
I might have a look at a Windows version in future, but don't have access to a PC at the moment. The code is open source on Github if anyone wanted to make an alternative version in the meantime. Nightwatch does make use of the Mac's location services and Apple Weather, but these should be easy to swap out. I don't know whether widgets ever made it back to the desktop on Windows, so anyone looking at porting it over might need to change the widget into a standard dialog.