Thanks for info.
I should have googled those operating systems and read about them. Those two operating systems are what web shop I was going to order parts from offers installed to sd card.
I have installed Raspbian to sd card before but was going to be lazy this time.
I found raspberry pi zero w locally so I will not order anything from that web shop after all. My spectrometer will be ready in few days. I will go and buy parts tomorrow.
Only thing that is missing for my experiments is colorimeter reagents. I might buy single aquarium water test kit so that I have something to experiment with before my reagents arrive.
I will print case instead of build it from Lego.