Tuesday, September 17, 2013

Where Oh Where Should the Fibre Cable Go?

Still puzzling over the alignment of the blue channel, the green laser was pressed back into service again...

Once more we felt like we'd improved things by resetting some of the optics & getting the spots to line up.  But when we took more images afterwards, we found there was still a blue focus gradient :(

As awesome as the green laser show is, it's all part of what Jürgen's now dubbed "The Alignmare"!

Hence it was a great relief when we heard that the Tech Ops guys had a long piece of hosepipe that they were using to explore ways to route the fibre cable up to the tracker.  Just a perfect diversion for those of us that could feel the tank's walls closing in...

Technically speaking, they cheated as they routed the hose from the top rather than the bottom, as will be necessary with the actual cable.  But it was an extremely helpful exercise none the less.

 They could figure out how best to negotiate the rho wrap, tracker & structure.

& then under the mirror & down the plug hole into the spectrometer room.

This is the view looking up from the spectrometer room.

The green actually looks pretty cool up there, pity the fibre cable's black!

The only scary place along the whole path is down near the bottom of the tracker bridge where we end up with a bit of a loop.  This is necessary so that the tracker can travel to the extremes of its envelope & so everyone will have to be Extremely careful when working up there so as not to snag or step on the cable.

Here Martin presents Ray & Jürgen with the proposed scheme.


Later Tech Ops boss Chris suited up - beak & all - for a grand tour of the instrument.

This evening was mayhem in the SALT control room with about 16 people up there, & it seemed like most of them were talking at once.  Being the overlap night there were 4 Astro Ops people, then the FIF team, the HRS team & a visiting journalist eager to hear all about everything!  Petri & Thea bravely continued to observe through all that - thanks guys for not kicking us out of your telescope!

Later on the crowd dispersed & the things settled down, allowing some more FIF & guider commissioning work.  The shimming this afternoon to get SALTICAM & the FIF parfocal did the trick & all the sign conventions were sorted out so stars appeared where they're supposed to.  

It was hugely encouraging to find that this system's about 15 times more sensitive than the RSS guider!  Even with a poorly stacked primary & a full moon blazing, it was possible to guide on a 16.5 mag star - Brilliant :)

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