Re: A 100m wide mirror -- some people need that . . .
<Building an Extremely Large Telescope (ELT) of the size now envisioned would be a huge engineering endeavour - not least because the instrument will have to be built thousands metres above sea-level to see the heavens clearly.
Everest almost has a sidewalk to its summit. Same with McKinley -- except maybe with more lanes for the heavy two-way traffic (was it 400 attempts per year?).
Dan
