Thanks Shenghui! I'll play around with these and try to make a graphic representation of the moon's path for marine navigation classes. A good visual goes a long way toward helping get ideas across. Al

Does anyone have an idea as to how the moon's GP could be graphed?

Dr. Wang,

This is so cool. Thanks for taking this on.

Your ability to navigate Mathematica is beyond mine. There are a few functions I don't understand, and the problem is slightly misstated. So I was hoping you could simplify this for me. What I'm looking for is a function that takes a date variable as an input, and returns a GeoPosition as an output. The position, of course, is the ground position of the moon (the point on earth where a line from the center of the moon to the center of the earth, would intersect.

Let me know if you can help.

Once again,

Thanks,

Tom