>>3945186Astro is shot at whatever iso speed you need in order to avoid motion blur and see darker objects like Jupiter's moons.
Also, high iso capabilities doesn't mean you have to shoot at its maximum value, it means that at iso 800, 1600 or 3200 the images will be as noise-free as possible.
That said, any modern cheap dslr like a D3500 has high iso capabilities without paying a lot, so it's not like it's a hustle or a big expense to get one. It just means to spend your money with that in mind.
