[CQ-Contest] Figuring TakeOff Angles?

[K4BEV@aol.com (K4BEV@aol.com)]

I should probably know this, but:
How can I figure out the best angles for various bands from my qth to another 
at a specific time?
For example:
West Tennessee to Florida on April 26 & 27, 2003.

I don't think I understand everything I know about the charts.

TIA, Don - K4BEV