# A telescope aperture the size of the solar system

If large space telescopes were placed in the L4 and L5 lagrangian points of Neptune's orbit, could optical interferometry be used to make an aperture the size of the entire solar system? What level of resolution could be obtained of earthlike exoplanets in the habitable zone of distant stars? From how far away?

What if these telescopes were placed on solar escape trajectory in opposite directions from the sun? Could this system be used to get higher and higher resolution images of exoplanets each year as the telescopes get further away from eachother?

• I'm sure this idea has been proposed multiple times in multiple different scifi works, but I can't for the life of me remember the names of any of them... – Starfish Prime Jan 2 at 13:54
• It's trivial to calculate the resolution limit. It's essentially impossible to establish and maintain a known path distance between those locations to a fraction of visible wavelength. – Carl Witthoft Jan 2 at 14:19
• @Carl--Is it "impossible"? If a continuous link is established and the relative orbital trajectories are known, wouldn't path distance be predictable and correctable for? – user34438 Jan 2 at 15:34
• @user34438 The problem is the accuracy. You are looking at an accuracy of perhaps 100nm over a distance of perhaps 10 billion kilometers. That's one part in $10^{20}$. At that scale things like passing gravity waves are a consideration, as is GR corrections from the gravity of most of the giant planets and .... – Steve Linton Jan 2 at 16:21
• – Steve Linton Jan 2 at 16:22