How do you make telescope objective lenses and mirrors?

3 Comments

1. campbelp2002 says:

   December 10, 2010 at 12:26 am

   That is becoming a lost are, because the cost of factory made optics is now so low. So most of the information has never been put online. What you can find is only a summary of a long and complicated process. The best information is to be found in (mostly out of print) books. See the source for a list of titles, then shop for them online or at a used book store.
2. injanier says:

   December 10, 2010 at 1:04 am

   Most amateur telescope makers make mirrors, not lenses, because they’re much easier. The basic process is
   1.Rough grind a glass blank to the appropriate spherical curve. You start with a flat blank and flat tool, and grind the sphere by moving the tool over the blank with grinding compound in between.
   2. Fine grind the surface with increasingly fine grit.
   3. Polish the spherical surface.
   4. “Figure” the polished spherical surface to make it paraboloidal.
   5. Coat with aluminum (usually you would send it out to a coater).

   Lenses are a lot more work because you need to form at least 4 surfaces (i.e. two pieces of glass), though they are all spherical or flat.