Is there a program to solve a metric TSP for 80 edges at optimum? i'm going to use the Christofides heuristic algorithm in order to solve a TSP for about 80 edges. Eventually i should have a solution, that is within the factor 1.5 of the optimum.

But when i'm finished, i'd like to check my solution but i don't know how. So i thought about using a computer-program to find the optimal solution to see, if my solution is within the 3/2-range.

i am not quite sure, if this is really possible or how long it might take. if it would take less than a month, i think, it would be worth a try.
It should be no problem to solve this instance with an integer linear programming based approach. You could try the online interface to the Concorde TSP solver.