One RSS lens group done!

Ockert, Janus & Jono finished cleaning & throughput testing the collimator doublet, so it could be re-installed in the spectrograph.  Its alignment was checked against the optical references set up with the alignment telescope - no adjustment required :)

Janus & Ockert checking the alignment of the collimator doublet after re-installation

It looks great again, all clean & with fresh lens fluid on board!  The cleaning of the two lens surfaces yielded a 2% throughput increase for this lens group.  The throughput of the collimator optics is being measured with an extremely nifty new lab spectrograph setup (more on that another day).  Next up they'll remove the other 2 lens groups, the field lens & the main group (consisting of the triplet & 2 singlets).

The clean & fresh collimator doublet back in the instrument

Here's the new base plate for the Fabry-Perot etalons, shortly after being painted.  This plate is made of invar, to eliminate the thermal instability inherent in the existing mounting hardware & which has wreaked havoc with the alignment of the etalons in the past.

The new etalon base plate is made of invar to be insensitive to temperature changes

All the while Wouter's quietly & efficiently capturing measurements & updating the CAD models for all of the RSS mechanisms while they're accessible.  Here he's got the poor slitmask elevator in plenty of pieces!

Where bits go to be modeled!

Up on the tracker it was time for the fiddly job of putting the M5 outer baffle back in place.  The ring's split on one side so that it can be twisted open & rotated in through the hole that the M4 steering wheel locates in.  Then 4 *tiny*, obnoxious little bolts have to go in to secure the baffle, grrr!

M5 outer baffle back in place

Here's the start of our carefully choreographed dance to safely transfer M4 from its box on the tracker platform to its mounting assembly above M5.

Eben takes a last look at M4 before passing it up to me in the payload

Fortunately the M4 steering wheel locates very easily in its mounting fixture & then one only has to insert 3 bolts (being careful of course not to drop them onto M5 below).  

With that - the SAC is Back!

On goes the big perspex cover to keep dust & muck out of there until its time to re-install the ADC & everything else above it... 

Is that a giant bug with a light sabre guarding the SAC?

In other exciting news on the hill...  Our resident pair of Verreaux's (Black) Eagles is keeping busy on the nest this year!

Black eagle on patrol

& today we got our first look at the new arrival - who's probably a few weeks old by now.  Doesn't have a single feather yet, just a white fuzzball, but already getting quite big!

Sutherland's 2016 Verreaux's eaglet!