Are you standing on a raised platform when you see the Half Dome?

This is what I get when I set the observer height to 20m, and increase the "max distance" to 300km (200km = ~124 miles so may not be enough).

https://img.incoherency.co.uk/6478

It's also possible that the half dome is too short and the sampling rate of the line-of-sight jumps over it!