I have a long list of calculations that I want to add to Calctool. I still want to keep up the expansion, and am willing to ad calcs on demand, but unfortunately it's hard to find the time. However, there are some calcs that it really does look like may never make it...
Into this category fall items such as Mie scattering, the Chinese calendar, and sextant sight reduction calculations.
Mind-numbing for my advanced years
In the past, in my young mathematical prime, I could derive equations for anything you could care to mention. Recently however, I have been stumped by some worryingly trivial problems. That's why, for example, there's no calc for the elastic collision of spheres.
Too much like programming
I'm no programmer, so even some simple calculations are outside my ability. Things that I'm sure are easy, like the manipulation of times and dates, and having textual inputs and outputs, are largely down to other volunteers to produce.