Wednesday, September 4, 2013

Some Very Heavy Optics...

The day started with Luke, David & Ant assembling the air-conditioning ducts.

& discussing a fair amount of "boy stuff", during which time David sought refuge in the bolting together of the small optical bench that will stand outside the tank.

Over in the electronics room next door to the instrument, Eddy worked on rebuilding the electronics racks.

Outside, Nicolaas, Johan & Denville sorted out the other end of the aircon.

Jürgen & I spent most of our time in the clean room getting the collimator & grating cells assembled & then mounting these 2 huge optics in their respective cells.  Unpacking & unwrapping the contents of all the crates & boxes was like a really good Xmas morning & then it became LEGO & Mechano *heaven* as we set about putting the various bits together.

Here's the >50 kg collimator mirror (+ perspex cover) lying snugly in its crate.

Shortly afterwards it found itself sitting on the optical table.

Here we've attached parts of the decentre adjustment mechanisms to the pads that had previously been bonded to the sides of the mirror.

The tip/tilt adjusters are on the back of the mirror.

The mirror had to be lifted into the re-assembled cell & the various pads aligned with the appropriate adjustment mechanism holes in the cell.

Then time for all Jürgen's crafty jigs, tools & tricks to get the ferocious adjustment springs screwed in. 

Thanks to Eben for making us a brilliant little tool to expedite the painful process of cranking on all the wing-nuts (in order to compress the spring & allow the retaining bolts to be inserted).

Here's the complete collimator cell seen from behind with the tip/tilt adjustment mechanisms installed.

Seen here from the front, with the decentre adjusters visible on the left & top surfaces of the cell & the white retainers in place in case anything unthinkable should ever try to happen.

& then, an added touch of class: the mirror cover includes an aligment target!

With the collimator mirror securely bolted to an out-of-the-way corner of the optical table, we could assemble the structure that supports the grating.

Next - the daunting task of safely lifting the several ton (or maybe just 60+ kg?) échelle out of its travel case & up onto the table.

Before unwrapping it & removing all the packaging material...

Happily there's a nice thick cover over the optical surface, but handling this enormous R3 million chunk of Zerodur is a fairly nerve-wracking matter.

But it Is Absolutely Magnificent!!

Best we put it in the right way around... ;)

Given the way the cell goes together, the grating had to be stood up on its side before being lifted into the cell.  Vertical posts were screwed into the optical table Just In Case anything precious decided to try to topple over.

Safely in position!

Seen here from what will be the top of the grating's "coffin" (as this part of the cell is affactionately known), since the grating will ultimately be suspended with the optical surface facing downwards.

Then time to attach more of the spring-loaded adjusters.

Here the spring for one of the decentre adjusters has been compressed & locked in.

Then the actual adjustment pin could be secured in place.

With the coffin's remaining side panels bolted on, the rest of the adjusters could be installed. 

By that stage it was nearly dinner time & it'd been a long day so we'll finish this tomorrow.  But before we go: one more pic of the magic grating with light passing through the Zerodur from the side...  Wow!

While all that was going on in the clean room - the thermal enclosure in the spectrometer room was getting decked out with loads more insulation.

This included putting together some of the Styrostone bricks that will pack around the vacuum tank.

& putting in the panels that make up the insulated floor, seen here beneath the foil that still encloses the tank.

Earlier David & Luke had removed all the legs & skates that allowed the tank to be manoeuvred into its new home.  These were then replaced with a set of pneumatic isolators that the vessel will rest on.

If the amount of discarded packing material is any measure of progress, we must be doing extremely well over here!  This pile just happened to be photographed before being whisked away to join all the rest that went before it.

No comments:

Post a Comment