Here We Go At Last! :) The HRS airfreight arrived in SA on Thursday 29 August & was sent up to Sutherland the next day. The 15 crates were carefully unloaded & deposited, as if by a giant optical Easter Bunny, all over the recently cleaned-out spectrometer room...
Fragile stickers Everywhere - here's the crate containing the large collimator mirror...
& the heart of the instrument: the enormous échelle grating.
The grating crate weighed in at 90 kg & was valued at slightly less than £200k, more than three million Rand.
To our mild horror - a shock-watch indicator on one of the crates had been triggered in transit, suggesting that something of unspecified unpleasantness had happened to it along the way :(
Although Crate #5 was one of the "cheap" ones valued at just £15k, it did contain some rather fragile (& of course essential) components, including the dichroic that splits the light into the red & blue channels, & the 2 cross-dispersers that separate the échelle orders. Careful inspection of the crate's contents would be necessary.
The other critical sub-system to be delivered to SALT (albeit via a more circuitous route than the crates took) was the instrument team from Durham's Centre for Advanced Instrumentation. Seen below are Eddy Younger (software engineer), Luke Tyas (who did his PhD on HRS & is currently based in Cape Town, aka SAAO/SALT's own Iron Man), David Bramall (mechanical engineer) & Jürgen Schmoll (optics guru).
Some gawking was in order while getting acquainted with the telescope.
Having done the tourist thing, the main job for the day was to get settled in (thank you Tech Ops for all the help, including providing safety shoes for us!) & then to open up the crates & check that everything's in good shape - particularly the contents of crate #5. Eddy promptly launched into getting the computers going & they all seem happy.
The rest of us set about moving the various optical components into SALT's mirror coating facility (the room fondly remembered for the many, many months spent in there during the SALT Image Quality Fix), which is again to serve as a clean(ish) room for some of the delicate optical work to follow in the next week or 2. With the optical bench in place, the first element to be inspected was the blue camera's Volume Phase Holographic Grating (VPHG) cross disperser - Beautiful...
The red camera's one looks fantastic too :) Whew! The "missing" sections of the cells are not a result of rough handling, but allow the cross-dispersers to be placed appropriately close to the camera optics.
Here's Jürgen unwrapping the dichroic - happily no rattling or scratching sounds while handling the well-wrapped beam-splitter...
Indeed, all's well with the dichroic too :)
This remarkable element splits the light into the 2 channels by allowing red light to pass straight through while light blueward of ~555 nm gets reflected.
Next it was time to check the mirrors for each arm - first the red fold flat...
& the spherically figured red pupil mirror.
Then the blue arm's fold flat.
The distinctive golden colour of the Zerodur (the same low-expansion glass ceramic that SALT's Spherical Aberration Corrector mirrors are made of) is visible when the mirror is viewed from behind.
Here's the blue pupil mirror - structurally identical to the red one, but with a different coating that's optimised for blue performamce.
Lastly, the grating was hauled out of the spectrometer room & placed in the clean room where it will be installed in its cell at a later stage.
We're quite relieved to have had a day to get organised up here before the shipping container is delivered. All the heavy weather in Cape Town led to some delays in getting the ship (which arrived in Table Bay on Friday evening) unloaded & the cargo through customs. However, it's now scheduled to travel up first thing tomorrow morning & be here before lunchtime - so we have another exciting day coming up!
PS - for those not familiar with the optical layout of the instrument, here's where all the bits mentioned above fit in...