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dangerous things


Ok, so here's my logic, i highly, highly doubt it's sound, but here it is:

Optical Telescopes work by gathering a lot of light and putting it in a smaller space.

More light = more better.

Reflector telescopes work off of this principle and can be very large with comparatively little weight.

Example: Dobsonian

Fresnel Lenses can be huge with very little weight, and can focus a lot of light into a very small space. 

  • Use a Fresnel lens as a primary refractor mirror and back it with the primary mirror from a newtonian style reflector. thus making the newtonian morror the secondary,
  • mount it on a slight angle in order to get the image away from the center of the primary mirror, 
  • use 2 of the internal projector lenses from the source TV to extend the range of the secondary image,
  • Use the stock Newtonian secondary mirror as designed,
  • Mount using steel rods and alt/az motors. 

this in all honesty, probably won't work, but who knows? I can only think of two major hurdles:

  1. Fresnel lens cross section - may lead to segmented (and therefore unusable) images
  2. much light = much heat = might melt things... like eyes... 

so yeah! That's the big idea, it would be interesting if it worked, though I can't imagine nobody's tried this before. there will have to be a lot of careful measuring in order to make sure things line up well... and accurate cuts will be a must. Also, keeping the Fresnel and mirror in alignment will probably be my biggest hurdle. truss rods could be used, and that honestly may be the way to go, but who knows?

Time to run home and dig out the small (28"?) lens I have and start measuring focal lengths.