I've never used the Pi OS on a PC, but supposedly you can.
I think you need to use the imager to make the SD card/USB work as a bootable device though, rather than just copying the files across. [Edit: assuming that's what happened - this isn't meant to sound patronising, just realised it might, apols.]
No need to get the image as well, that's included in the imager -
https://www.raspberrypi.org/downloads/
Interested to see how this turns out, an all sky cam's on my list of things to do - cheers, Mike