Fortran to IDL Conversion

I have an astronomical program written in Fortran that I want translated into IDL. It involves using a Box Least Squares algorithm to detect periodic signals in a string of numbers. The Fortran program is about 70 pages long. Successful completion will be when both programs produce the same detection data from the same source file. Program is reasonably commented and I have access to the original Fortran programmer if there are questions. Must be strong in math.