This aplet converts your 39/40 to a complete RPN scientific calculator, it has the classic 4-level stack plus LASTx. It's written in System RPL and runs with no noticeable lag. This version supports real numbers only.
This is a modified version of the Sparcom Celestial Navigation Pac, patched to work on the 49/50 and virtual machines. It includes these improvements: better display formatting, ADV program now reaches the expected result and it can run on real or virtual machines.