NavList:

I have an fx-82AU Plus II. if I switch it off (or the device times ou)  any formula I have entered is lost. After reading Bob's post I  looked at the specs for the fx-9750. It is programmable so maybe it would be a better option for me? But it has two disadvantages - the price and the lack (as far as I can tell) of a sexagesimal button. To do  sexagesimal arithmetic you must bring up a screen and select the function which is a few more keystrokes and requires more thought than with  the fx-82AU.

I have a choice of the fz-82AU which has a sexagesimal button but I have to re-enter the cos formula if the power goes off. At the start of the school year it is usually on special and can be picked up quite cheaply.

or I could buy the fx-9750 whiich saves the formula(s) but does not provide easy sexagesimal conversion and costs a lot more.

The cos formula is easy to remember and can be entered quickly if the data has been stored in the memory registers (with the help of the sexagesimal button)    sin h   = sin A  sin B +- cos A  cos B cos C.

To me it is a no brainer - the fx-82AU wins hands down because I do not have to think about sexagesimal arithmetic. Also, because I am an armchair navigator and live ten minutes walk from a shop that sells batteries, I do not need a solar powered calculator!!!