XPost: sci.space.policy   
   From: bondage@frontiernet.net   
      
   alexterrell@yahoo.com wrote:   
   >   
   > Just seen some pictures of Hubble, and The "Very Large Telescope"   
   > (original name) in Chile. It made me think.   
   >   
   > With a reasonable space based industry, moon mining, metal working,   
   > aluminium and glass production, precision engineering, how big an   
   > optical telescope could be built in zero-g?   
   >   
   > What are the limits? Could a 100m diameter optical telescope be built?   
   > what would it see?   
      
      I don't see any reason in principle (as opposed to the actual   
   engineering) why you couldn't make a parabolic mirror of almost any   
   size.   
      
      Of course, where any planetary surface is involved, sooner or later   
   there will be deformity and sag issues. And a sufficently massive mirror   
   (with associated framework and/or tube up to the focal point) in free   
   fall would be difficult to steer and track. Espically if orbiting deep   
   in some gravity well, where there would be a tendency to line itself up   
   with the planet's center of mass.   
      
      But you'll likely have observed plenty of neat new stuff (including,   
   I would think, direct imaging of extrasolar planets) well before   
   reaching those limits...   
      
      
   > As for radio telescopes, what are the limits are baseline inferometry?   
   > what would a few telescopes, each say 3km across, in solar orbit, say 1   
   > billion km apart be able to achieve?   
      
      Problems here are somewhat similar to those in optical, except that   
   minute deformations of the parabolic surface are less critical at these   
   wavelengths.   
      
   --   
      
      You know what to remove, to reply....   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)