Summer shutdown: SX primary recoating… and much more!

Monsoon season is summer shutdown time for the observatory. Don’t think that not looking at the sky means nothing much happening under the LBT enclosure on Mt Graham! Much work is going on to clean, repair, maintain, or upgrade many of the components of the observatory.

Every year, one of the two 8.4m primary mirrors gets a facelift, I mean a fresh aluminum coating. This year, it is SX (the left mirror’s) turn. On most telescopes, the mirror would be removed from the telescope and carried to a near-by lab to be cleaned and re-aluminized in a vacuum chamber. At LBT, the mirror stays on the telescope. The old coating is removed and the mirror washed while in its cell. The vacuum chamber, actually half of it (the bell jar) comes to the mirror and mates to its cell to form the vacuum chamber. 

The bell jar waiting in the high bay to be lifted to the telescope floor

 

The bell jar on the SX primary mirror

Once the aluminizing is done, the bell jar goes back to its storage place on the first floor of the observatory. The mirror got a new shiny coating without leaving the telescope… The whole process went very smoothly. Kudos to all involved!

 

The three SX bent gregorian focal stations  (from left, Linc-Nirvana, LBTI, and LUCI1) (top), 

and their reflection in the freshly recoated SX primary (bottom)

Here are some of the many activities are going on for this 2013 shutdown:

– Replacement of the hoses bringing glycol to the many chillers cooling mirrors, instruments, and their electronic cabinets. Not an easy task, as these hoses are going through the telescope azimuth cable wrap!