Looking down the barrel

A view down the RSS camera barrel, through the polarising beamsplitter, towards the CCDs

A sunny winter's day in the Karoo

Some tests are still being done on RSS to establish the before-cleaning baseline, while up on the tracker the guys continued working on the ball-joint replacement.  The other two ball-joints show more wear than the first one did, so it's really good that they're being replaced before they had a chance to fail.

RSS at its operational angle with calibration lamps attached below

Jono, Nicolaas & Eben replacing the next tracker ball-joint

Meanwhile - after lunch Ant popped outside to take advantage of the beautiful day & give his quad-copter a work-out over the plateau - check out the YouTube clip!

Replacing the tracker ball joints & checking out M5

While most of the country took the day off to go cast their municipal election votes, members of the Tech Ops crew dashed out early to vote & then settled in for a busy day at SALT.  Eben, Johan, Timmy & Thabelo tackled replacing the tracker ball joints: creating the various custom tools they needed & establishing the process on the most accessible of the joints (the one on the down-hill side of the tracker).

Struts are used to support the tracker while the hexapod legs are disconnected to allow the ball joint to be replaced

The ball joints sit at the apex of each pair of hexapod legs

Relieved to see that the old ball joint was still in extremely good condition

Keith kept himself busy with RSS functional tests & various members of the team from Cape Town (Ockert, Janus, Anthony, Éric & Wouter) arrived throughout the day.  In the evening we took turns climbing inside the now-empty non-rotating structure of the payload to take a look at the top end of the spherical aberration corrector (SAC).  Next week we'll clean the top, upward-looking mirror in the SAC (M5) in a bid to improve the throughput of the telescope.

Ockert & Janus figuring out how to get comfortable within the confines of the payload

A Rather dirty mirror!

The mechanicals will keep going on the ball joints tomorrow & once all the "before" RSS tests are done, Ant can get on with testing the instrument's new spare control PC.

Now for the payload...

Today's mission for Eben, Nicolaas, Etienne, Denville, Timmy & Thabelo was removing the payload.  To simplify that, most of the major chunks were extracted while the rotating structure was still on the tracker.  The FIF (fibre instrument feed), HRS guider, SALTICAM & ADC (atmospheric dispersion compensator) all skipped the crane ride.

Extracting the heavy, fragile bits from inside the payload

As with RSS, the payload was lifted out & then the structure rotated away from underneath it

It was then carefully lowered to the ground floor with the dome crane

RSS (left) & the payload (front) now share the spectrometer room with HRS (in the black enclosure on the right)

Tomorrow's a public holiday due to local government elections, so work will only start after voting in the morning.  The electricals need to finish getting RSS & the payload operational while the mechanicals will start with the daunting task of removing pairs of hexapod legs to replace the tracker ball joints.

RSS comes down!

The 2016 shut-down action began today with RSS being removed from the telescope.  Before that could happen, *everything* had to be disconnected, the etalons were removed & the HRS fibres were carefully stowed out of harm's way.  Eben & his team then did a superb job of safely relocating the spectrograph from the top of the tracker to the spectrometer room on the ground floor beneath the telescope!

Removing the etalons

HRS fibres stashed in the blue tube

We have lift-off! 

This is why cranes get checked & certified!

RSS approaching the hatch in the first floor

Docking with the frame that RSS will call home for the next month or so

The focus usually tends to be on glamorous scientific results, but it's these sorts of technical efforts that actually make observational astronomy a viable pursuit.  To provide a feel for what all goes into taking care of a facility like this, we'll aim to post at least one captioned pic per day throughout the shut-down!

SALT Engineering Shut-Down

We wish to remind all PI's with currently running 2016-1 programs that there will be a scheduled SALT shut-down period from August 1, for up to five weeks.  The major engineering tasks during this time include servicing the RSS, installing components associated with the tracker upgrade project, the cleaning of various optics and work on the tracker payload.  No observations will be possible during this time as the telescope will be completely offline.  The first week or two after these tasks have been completed will involve the recommissioning of the telescope and instruments, although science observations will be attempted on a best-efforts basis.  We look forward to getting back on-sky with better throughput in September, when the Sutherland weather will hopefully have improved as well!  Daily updates will be posted on the blog during the course of the shut-down so watch this space...

Night Log 2016-07-31

SA: Encarni
SO: Veronica
Others: Keith

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Summary
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Backwards for once: Foggy start of the night and then the skies magically cleared of all the wet stuff by 2am and we finally got some science data! And the lucky winners are:

2016-1-DDT-002 P0 RSS (Fast transient exploration)
2016-1-MLT-007 P0 RSS (Observations of supernovae, near and far.)
2016-1-SCI-048 P1 RSS (We propose to obtain phase-resolved spectropolarimetry of magnetic CVs with SALT. )