the Extremely Large Telescope (ELT). With blanks made by the German company SCHOTT, this vast structure was the biggest that the company had ever made. But the mirror didn't just need to be big.

The true test of the amateur astronomer is building their own telescope. Grinding and polishing your own mirrors is a long, arduous process. Instead of lapping the blank by hand, Laurie Hall built ...

There were actually two mirror blanks, both made by Corning ... Some experiments could use the telescope the way it was, but others were impossible. So for three years, the telescope did the ...