Electron Microscopy. Often used to see very small structures at high resolution. So 1.2 Å is 1.2 angstrom, or 0.12 nm.
Edit: I should add that often at really high magnification, there is a lot of noise, so the joke is that non EM people would just see static. Not too far from the truth. Practice helps seeing the patterns!
I just used NixOS daily for maybe a month? I really love how it’s designed, but I had to give up because there were just so many small fixes I had to do and I found myself banging my head against the wall when I couldn’t build something that depended on python-tk. You will see this criticism around a lot, but the documentation just isn’t there yet. If you try to search for a fix, the packages have changed how they’re configured since a solution was posted or they depend on a Nix flake which 50% of searches say not to use because it’s experimental and 50% are all in on flakes.
I have since moved back to Arch, but I’ve started to use the nix package manager for some cases since you can on-demand non-permanently install a package.