Complicated Question, hope I don't confuse......

First of all, thanks for taking the time to read this. I have been considering creating an excel document for something but do not have the inherent know-how of Excel to do so. I am no Excel expert but I can catch on pretty quickly. Here goes:

I am on a ship that has internet access while underway via satellite. This is good, except at certain headings our mast blocks the satellite from our receiver (about a 50 degree range in heading). The satellite is in a geo-synchronous orbit and is fixed on the equator so it's coordinates never change. I would like to create an excel document that you can input our ship's coordinates into and it will show at what heading the mast will block the satellite from our receiver. I would also like it to display a red field on a compass showing the range of heading that the mast blocks the satellite.

If you need more information, let me know. Hopefully someone can help me with this as this will be very VERY helpful for our ship's operations.

Thanks again for your time.