2 billion km = 2e12m, not 2e9 The fact that individual stars can be seen doesn't necessarily mean the telescope has a resolution equal to the angular size of t

2 billion km = 2e12m, not 2e9 The fact that individual stars can be seen doesn't necessarily mean the telescope has a resolution equal to the angular size of this star. A point source will be apparent even if it isn't resolved. Otherwise we could never see stars with our naked eye.