Wednesday, November 24, 2010

What's been happening up at SALT?!

"No news is good news" sums up the past few months...  The IQ blog may have dried up, but an awful lot's been happening, both at SALT & in Cape Town where people have been working on SALTICAM & some RSS bits.  Clearly it's time for an update :)

I'm ashamed to admit that I haven't taken any recent photos of the SALTICAM work, despite the fact that some very cool things have been happening - apologies to the devoted optics groupies out there!  In addition to all the other upgrades to the instrument, the integration of the autoguider required that the relevant lenses be transferred to a new rear barrel which will accommodate the additional hardware.

In testing the optics again afterwards (with the interferometer used for the SAC work,) some problems became apparent & Darragh found himself nursing a sequel to the SAC IQ drama.  Fortunately, with his black belt in Zemax & the help of Craig, Tim & Francois, SCAM's IQ problems proved no match for the instrument PI & the system was soon whipped into good alignment & the autoguider could be installed.

As for the action in Sutherland - a great deal of work's gone into every sub-system, including re-wiring the entire tracker, eliminating sources of heat within the telescope enclosure, improving the primary mirror alignment process, getting the payload re-organised &, of course, (all the king's horses & all the king's men) putting RSS back together again.  The payload was always a bit of a nightmare - here's an old pic of what it used to look like.

A nifty new electronics rack now takes care of all the major systems within the payload & will simplify life enormously for everyone concerned.

The finishing touches were being applied early last week.

Another addition to the payload is B-Cam, a backup acquisition camera.  The optics had been in hand for a while already, but the rest of the instrument could only be designed & manufactured post-IQ.  The new hardware was aligned last week & the Apogee CCD used for the IQ on-sky testing will be the detector.

In the RSS department: the instrument's really looking like a spectrograph again & Peter's thumb seems to be making an impressive recovery too :)  Before returning home from the SALT Board meeting, Ted spent some time checking out the Fabry-Perot side of things (the high resolution etalon's been repaired & is happy again). Then the Wisconsin team (Ken, Mike & Bill) established camp in the spectrometer room for a couple of weeks & worked through an extensive to-do list with Peter, Anthony & the rest of the gang.

Successful hardware interventions included extracting the air bubble in the collimator's lens fluid, sorting out mechanical clearance issues with the wave-plates, adjusting the alignment of the detector, fixing the sag in the camera articulation mechanism & baffling up as much of the camera system as possible.

A lot of progress was made on the software side as well, such as the development of auto-focus routines, the introduction of various checks to monitor & report on the status of different mechanisms & also to control the gratings, filters, wave-plates etc.  The overall level of user-friendliness has increased enormously since those dark early days of SALT spectroscopy!

Meanwhile, upstairs, the assembly holding the Apogee camera in place had to be removed from the payload so that the guys can access the Rho stage to go about fixing its wobble.

The flying saucer type contraption floated down elegantly...

& came in for a gentle landing down in the loading bay.

Then on Friday morning, the payload was rigged up & cleared for take-off.  Thanks to Janus for providing us with photos!

Vic courageously shouldered the responsibility of striking the technically-demanding Teapot pose during this delicate lifting procedure ;)

Jeremy Clarkson might ask: "How hard can it be?!"

Good job chaps, although now there's nowhere to sit inside the non-rotating structure anymore...

The "still to do" list consists of, amongst other things, testing the atmospheric dispersion compensator (ADC), completing the testing of SALTICAM, installing & aligning it within the payload (this will be done with the payload back down on the ground) & then once that's all back on the telescope, the spectrograph ought to be good to go up as well.  Lots happening & much exciting stuff to follow over the next few months :)

1 comment:

  1. Ah one can spot a Lisa blog entry a mile away. I think blogging should be included as a required astronomy PhD course!