If you're not camping overnight can you still watch the stars ?

Yes. On one side of the road there is access to a large field that is free. Please either plan on not using a flashlight or using red light (it explains this in the park info board). There is also camping on that side, but you typically have to reserve the sites. On the other side of the road, there is all night parking which means if you're parked there until dark, you're locked in until morning.

Yes