Wednesday, August 31, 2016

SALT's back online!

What a difference 30 days can make...  The RSS was brought down on 1 August, it's been taken apart completely, extensively over-hauled & put back together.  So today it was time to get it back on top of the telescope!

Gone - almost without a trace!
Looking & working better in every way than it did when it came down, the spectrograph was wheeled out into the loading bay outside the spectrometer room.  

The lifting team getting everything set up
With RSS rigged up, released from the support frame & ready to ascend through the hatch in the floor, it was project leader (& very happy, but still anxious!) Ockert's cue to fire up the inspirational soundtrack :)

Cue the music!
The crafty scheme to pull back a day & thus restore the schedule was to lift the instrument with the detector cold.  That required keeping the cryo-cooler attached & running throughout most of the lift & installation.  It added a bit more complexity to an already daunting procedure, but it worked a treat as it allowed us to get on sky as soon as all of the cabling/fibres/hoses etc had been reconnected up there.

Cryotiger in tow this time!
An enthusiastic crowd was in place to take a last look as the spectrograph (& cryo-cooler!) paraded past the catwalk...

Quite a crowd gathered for the occasion
The structure was then rotated into place (by Ant down in the control room) & then with the landing zone within reach, the compressor was disconnected & taken back down to its igloo.

Time to disconnect the cryo-cooler
Dome crane operator Denville could then tweak the dome rotation & lower the RSS towards the tracker, to be guided down carefully by the many hands below. 

Being helped along for a smooth landing on the tracker
Timmy & Jono, perched on the edge of the world, could later crank down the chain hoists to slacken the lifting slings.

Try not to think about where Timmy was actually standing!
With all the life-support systems connected up top, the control room filled up as Fred did a coarse mirror alignment (a fine alignment was out of the question due to the high the wind).

Waiting to see whether the telescope really is back together again
The first pointing was to a spectacular target - M16, also known as the Eagle Nebula, a star-forming region in the constellation Serpens.  As usual, a picture was worth at least a thousand words!  It immediately showed that the telescope pointing's good, the image quality looks fine (given that we could not do a fine alignment of the primary because of the wind), even the guide probe mapping was still close enough to find a guide star.  

2 sec SALTICAM image of the Eagle Nebula!
Retracting the SALTICAM fold mirror in the payload then allowed the light to reach the RSS & that image looked great too...  

20 sec H-alpha image taken with RSS
A quick (5 sec) spectrum of a bright star in the field confirmed that the slitmask, grating & filter mechanisms are all working as they should too :)  There's plenty more testing & on-sky performance verification to be done, so now it's mostly over to Astro Ops to put everything through its paces & check that all's well before getting back to full science operations in a few days time (weather permitting)... 

We've blasted through August, so now it's getting Springy in Suthers
It's been an incredibly busy month up here.  Huge thanks & congratulations are in order for a superb team effort, & particularly to Ockert for doing a fantastic job of organising & leading such a challenging project!  We eag(er)ly await a photometric night to take throughput measurements!

Watch this space!

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