At Keck we regularly move pieces of glass up to two meters across and weighing hundreds of pounds. These optics are nearly irreplaceable, visions of catastrophic damage to one of these pieces of glass is the stuff of nightmares. An observatory is built around the telescope, hundreds of tons of steel supporting the all important optics. While damage of any sort is a concern, much of the critical equipment can be repaired without major issue. It is the optics that are much harder and more expensive to replace. While these pieces of glass could be re-manufactured, it would probably take a year or more to accomplish.
At Keck we had recently undertaken a full review of our optics handling procedures. Every step of the process, every piece of equipment was subject to scrutiny. The procedures reviewed by a committee of internal and external reviewers. The goal was to prevent just this sort of incident, to protect our invaluable glass.
Photos of the damaged CTIO secondary and descriptions of the incident are a powerful example of what can go wrong. Something that will be in the back of everyone’s mind next time we are moving a piece of big glass.