Saturday, July 20, 2013

Installing the Fibre Instrument Feed

Much effort in the lab over the past months has got the SALT Fibre Instrument Feed (FIF) ready for installation within the payload's FIF bay. 

The payload's empty FIF bay.
 The payload's auxillary mirror folds light emerging from the atmospheric disperson compensator (ADC), situated above the spherical aberration corrector (SAC), into the set of fibres that will feed the HRS.  The FIF's translation stages allow the appropriate "star" & "sky" fibre-pairs to be selected for the desired HRS observing mode (either low, medium or high resolution mode, or the high-stability mode).

The FIF stage assembly & part of the instrument's autoguider, ready for installation.
Here's Eben & Janus lifting the FIF up to its bay in the payload's rotating structure.

FIF going in!
Without much fuss, the 3 attachment points were secured & the FIF was In!

Securely in position in the FIF bay.
Next, Janus could attach the test fibres to the stage.

Test fibres connected to the stage assembly.
& connect up all the cables...

Cables connected...
Moment of truth: can the software talk to the hardware & make the little green lights go on?  YES It Can!  :)

The FIF's LabVIEW interface.
The software could also move the stages, but one of them didn't go all the way to where it was commanded to & so the stage assembly had to be brought back down for inspection.  The section that the autoguider will attach to could remain in place in the FIF bay, a really nice Tech-Ops-friendly design!

FIF bay with the incomplete autoguider parts still in place, but the FIF stage assembly removed.
Inspection quickly revealed that an anti-backlash nut on one of the lead screws had locked up so the offending part was removed for now.  After some more cable-wrap management, the stage assembly was re-installed & successfully tested over its full range of motion.

As is so often true in life, getting the troublesome nut out of the way solved the problem...
The only remaining snag was the weather which didn't permit on-sky testing.  Forecasts for the weekend look promising though so we hope to send starlight down the test fibres in the next day or 2!

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