I'm pretty sure that the text I used is plagiarized from Practical Astronomy with your Calculator by Peter Duffet-Smith. I don't have my copy of Meeus here but I'll get it - be patient. You're probably right that a Julian day is a double and that a Julian day number is an int. Either way a function that returns a double is much more useful since a double is required for astronomical calculations and it can be rounded to an int. Stay tuned.    Senor Cuete  