How and why do you use your HP calc?

[Helix]

I can't live without a calculator. I have very often some calculations to do, for various reasons. I guess I think mainly with numbers…

My current calculator is the HP 50g. I like its power, its extreme flexibility, its big screen and infinite stack, which allow putting intermediate results on the stack, instead of storing them in registers or printing them. Another wonderful feature is list processing, which in many cases avoids writing a program. I rely heavily on list processing and stack operations.

I use also EMU48 on my laptop, even more often than my physical 50g. RPL is great in this case because it saves a lot of keystrokes, and that's especially convenient on a keyboard not designed for a calculator.

More specifically, I'm interested in astronomy and optics, as a hobbyist. Both domains are math-related. For example in optics, I'm working with a lens design software, but there are still calculations to do to choose the initial values, to verify the results, to understand what happens, etc.

I have also other scientific interests. For example, several years ago I've tried to learn and understand fractals and chaotic systems. Last year, I've begun to learn special relativity. In both cases, there are examples or exercises in the books which require a calculator.

I've tried the HP Prime emulator, but I fail to understand its logic. I find this calculator very difficult to learn. In comparison, the RPL logic is desperately simple.
For me, the HP prime is not a "HP calculator". It's a calculator made by HP. That's different!

I'm also interested in programming. I've discovered recently that writing C programs for the 50g is very easy with HPGCC 2.0 and the Programmers Notepad, so I've decided to learn C, just for my knowledge and my pleasure. C is a universal language which can be used in many devices, whereas HPPL is useful only for the HP Prime.