[coffexx]

Interestingly in the astrophotography hobby space, purpose built, cooled, OSC cameras without aa filters exist around the same price points as DSLRs intended for terrestrial use. To buy one though you really have to be into it (or have a lot of spare cash), as you can only really use it for astro work.

If someone is just getting into the hobby they're probably using a relatively low focal length scope or lens with a DSLR they have laying around. What that means is a wide field shot with lots of tiny stars. Many of those stars might only fit within a single pixel unless they were very bright.

In that specific scenario an aa filter has the advantage of providing more natural star colors, as the light that otherwise might only have hit a red or blue pixel in the bayer matrix is instead spread out into the other colors.

It's less of a beginner thing to do, but if your shots are extremely under-sampled like that, dithering your subframes and using drizzle integration in post helps a lot with blocky (OSC + Mono) and off-color (OSC only) stars. That is, assuming you're trying to stack exposures instead of it being a once off shot.