Do you have a name for this program? It sounds a lot like an urban legend - when would you ever find it easier to parse a date out of an astronomical program than to use actual date handing capabilities from the system or a library?
The one that I described I first remember hearing about in undergrad. I heard it from an astronomy student. I guess that makes it an urban legend, but a highly believable one. In my experience inexperienced programmers are very good at unexpectedly repurposing whatever they happen to know for new purposes. And in an astronomy department it is easy to find inexperienced programmers with astronomical routines at hand.