Monday, October 14, 2013

A Busy Week Goes By

Another busy week up here - starting off with some mods to the FIF guider to prevent the cable wrap from slipping out of place & causing problems.  A thin plate was attached to act as a retainer for the cables & a few other tweaks were made - thanks Eben & Ockert!

& we got to welcome a new electronics tech in the form of David de Bruyn.  Here he is, learning the ropes & getting his tracker legs - Great hat by the way :)

Those of us that're obsessed with fibre safety will sleep a little easier now that the last exposed section on the top of the tracker has been covered with a nice solid plate.  Dankie Johan!

Time for some shameless Fabry-Perot marketing...  On the last night of David B's week as SA, he shot this awesome H-alpha sequence of a supernova remnant that had been discovered with the XMM X-ray satellite.  Really neat to see different parts of the nebulosity light up as one scans along in 10 angstrom wavelength steps.

As if we haven't had enough tracker excitement lately, Wednesday was declared H4 service day.  This is the bottom left hexapod, as seen from the tracker platform - the rest will get their turns in due course.

It's a bit disconcerting to climb up to install the fibres when one of the hexapods is simply Not There! 

Happily the fibres all went back in without too much fuss.  The sky ones are quite a challenge, but the object fibres are easy enough to reach & poking a small mirror in behind the FIF confirmed that they're all seated properly.

With the HRS guider, the FIF & the fibres all re-installed, & the sky looking great, we were good to go!  Except - our arc exposures showed no lines?!  Turns out the shutter controller wasn't doing enough to drive the shutter so it wasn't opening at all - aaargh!!  Toggling it manually didn't help & so this looked like a show-stopper (this is the spare controller, the original's already been sent back to Durham for repairs).  Enter the heroic CfAI team: offering expert advice, after midnight, via Skype & email - including ways to reconfigure the shutter controller & thereby saving the day!

We got the big screen in the control room set up to display all the remote desktops needed to run the HRS software...

From everything being in pieces earlier in the day, we managed to get on-sky & send light down the fibres.  Here's the exposure meter running on a 7th magnitude star, albeit with thick clouds wafting over...

Absorption lines galore in this high resolution blue frame of HD10180!

SALT Astronomer Encarni sneakily snapped this shot of us at 04:50 on Thursday morning...  While we may look fairly shattered, it'd been a long day & we'd overcome a number of significant obstacles before managing to get data in each of the 4 modes.  So in spite of all the software, shutter, payload & telescope issues, it ended up being a Great night! :)

After several weeks of reasonably good behaviour, Luke was eventually rewarded with a trip up the CCAS tower...  

CCAS is undoubtedly one of the niftiest SALT locations - thanks Francois!

After that we decided to fire up the iodine cell on HRS & see how that works...

Heating a small iodine crystal inside an evacuated glass tube up to about 80 C causes the iodine to sublimate & the light passing through the cell ends up with a rich forest of absorption lines superimposed.  This allows for extremely accurate radial velocity measurements - which will help us to hunt down exoplanets in future!

Here's what a red frame with the iodine cell on looks like - a huge number of absorption lines down at the blue end of the red chip.

While waiting - in vain - for the wind to drop on Friday night, we started running HRS tours.  The admission fee is wearing a silly outfit, having your photo taken & being published on the blog ;)

The weather was infuriatingly bad for 3 consecutive nights so we took all the calibration frames we could stand.  These included some rather funky ones (shown here with the intensity inverted) which had HRS's internal Thorium Argon arc lamp going down the one fibre (upper trace) & the SALT calibration system's quartz-tungsten-halogen flat field lamps going down the other (lower trace).

Eventually we were driven to decorating Luke's night lunch & we decided to pay homage to our far-away & much-missed colleagues back in Durham...




& David!

OK - enough of  that, it's midnight & Luke's hungry...

In fact, anyone with such neat, legible hand-writing surely needs to be regarded with extreme suspicion, if not fear as well.  How on earth did he ever get a PhD with writing like this?!


That's is it from me for a while - 6 weeks since we started all this & it's time for a break...  Thanks to the Sutherland Black Eagles for an incredible send-off as I drove down past the cliff yesterday afternoon!

& to the pair of Jackal Buzzards for the escourt out the observatory gate.

Good luck to Luke as he holds the fort until the Durham guys start to reappear in about a week!  Also to Paul & David for the blue camera surgery which I hate to be missing - please take Lots of photos...  See you all again on the 10th of November!

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