Welcome aboard! There are many planetary and moon candidates for Sun blotting, but from my testing I've found the sun can be blotted out with as few as one Aurora! It just has to be very close :-)
I believe an attempt at space based blotting was attempted with many Auroas, but finding think I was there for that.
Whenever and wherever someone shouts "Free booze!" or "One round for the house" our Auroras will blot out the sun quite instantly.
Or the moon.
Or both.
Depending on time and structure of the respective star system.