Lil' Bundles of Joy!

This morning as I walked into our integration lab, I was reminded of the warehouse scene of "Raiders of the Lost Arc" - the floor was covered with boxes about as far as I could see!  I counted about 70-some pallets of 24 boxes each.  And what could consume so much floor space in our lab?  GLASS! 

It is time once again to cast a mirror, and that calls for sorting through more than 20 tons of Ohara E-6 borosilicate glass (a Pyrex equivalent).  The sorting process takes a few days, and commences right after the Thanksgiving break, so they've moved in glass, sorting tables, light boxes and tools to put together their assembly-line process to inspect every chunk of what will become the next mirror substrate - the next Giant Magellan Telescope (GMT) mirror.  Each box holds about 10-12 kg of glass, and each block will be cleaned and inspected for flaws and impurities (most of these show up as stress concentrations under cross Polaroids), and sorted for where it should be placed in the mold.  The best glass is kept for placing in the mold last, so it will remain on the faceplate of the cast mirror.

While I've never been called to assist with the sorting process, it is fun to watch the crew working together in the assembly-line process.  After the glass inspection, they will also inspect the mold, which has just been through a pre-fire process the last week.  The glass will be loaded into the mold just before the Christmas shutdown, and the casting will start in January.  The process of transforming raw chunks to finished optics continue!