How are astronomers reducing the weight of telescope mirrors?

5 Comments

1. GeoffG says:

   January 13, 2011 at 3:47 am

   Mainly by making them a honeycomb structure, rather than solid glass. They are also making mirrors out of thinner glass blanks, and then supporting them in better cells. A third way is by making the mirrors thinner at the edge and supporting them at the centre.
2. Ben says:

   January 13, 2011 at 4:01 am

   There’s a lot which they can do with solid mirrors, but an increasingly popular way to have large sized mirrors without excessively heavy materials is to use rotating liquid mirrors, using mercury or similar reflective metal liquids.
3. Vincent G says:

   January 13, 2011 at 4:06 am

   Telescope design is not really something that is done *by* astronomers, by the way.

   Advanced telescope techniques to allow larger mirrors without too much mass are:
   - hollowed core (as opposed to thick slabs)
   - multi-mirror approach with active alignment systems (where the mirror elements are mounted on actuators that correct their position to keep them in focus, instead of relying on the rigidity of a large monolithic slab of glass)