South Pole Diaries 1998/99

   

   


Saturday 23rd January

From Michael Burton.....

Well after a couple of days of brutal weather, the clouds have gone, the wind has eased and the Sun has come out again, and even the Hercs have started arriving again! Then there's been the the steady chug of caterpillar tractors running up and down the ice all day dragging giant snowploughs behind them as they clear up the great snowdrifts that have accumulated behind all buildings, and re-grade the skiway and other walkways about town. Its gives those of us who are temporary residents a little feeling for what it's like in winter when Mother Nature is allowed to reign unchecked and the snow if left to lie where it falls!

The good weather could be seen as a sharp line of blue sky way to the north this morning (that grid N) moving slowly towards us with the wind. About noon the bisecting line between blue sky and cloud was directly over the station, with at one point the AASTO in brilliant sunshine and the Dome under cloud. An interesting observation of a change in the weather system moving unhindered across the continent.

The first Herc in brought us a replacement PZT for the secondary mirror of the SPIREX telescope, and its now installed, though not without a few concerns as it doesn't seem to have been manufactured exactly the same way as the others we have. I guess we'll know fairly soon whether its going to work.

Al Fowler is happy, which is a good sign for all! Abu is now definitely on its cooling curve, and after 48 hours is getting close
to the cryogenic temperatures we need it at if it is going to function. Another 10 hours on the pump and it should be there. The little extra load we placed on the system this year has been enough to take the pump right to the hairy-edge of what it can cool down, something Al was unaware of until he tried. So it looks like we may have a working telescope and instrument for the season!

The AASTO, on the other hand, is definitely an unhappy camper right now. The servicing crew have been and gone, and left it without its power system on!! There has been some considerable trouble with the cooling system, with the freon which is supposed to circulate and remove the excess heat, leaking, and the radiator itself being blocked. Our little portacabin on the ice has been getting up to about +40C inside, while the windchill outside was below -50C! Definitely very toasty inside, especially in our polar clobber, and not good for the freon which goes gaseous at these temperatures, thus exasperating the leaking! In an attempt to fix the blockage by the trusty method of wacking the radiator and pipe with a wooden stick it appears that another valve was cracked causing freon to leak once more! So the service crew have decided that drastic action is needed, which is to take the radiator off completely and bring the system inside for a thorough going over. Only, now the Hercs are flying again, they have headed north on another job, and wont be back till sometime in Feb! Charlie, our trusty winter-overer has decided to look into the problem himself and is now searching for leaks in the radiator by pumping down on it, and running a helium leak checker over it, just like you do for any cryogenic vacuum system! This might be overkill for our system, but at least we should know everywhere it has micro-pores in it afterwards!

Since the Sun has come out again I decided it might be as well to place the sunglasses back on the webcam, but ran into a minor technical hitch. The hi-tech blocking-filter-removal-module (BFRM) that Andre had designed (a piece of string with a bullbog clip on one end which you pull through a hole in the back of the camera mounting) worked great at raising the sunglasses, but not so well for putting them back on again as they run into the camera body! Well I discovered this at about 6am today, which is about my bedtime round here, and I was too tired to do anything about it. But fortunately Matt, who
wakes up about that time, spotted the problem and went to it with a screwdriver, removed the plexi-covering around the camera, fixed the sunglasses, and put it all together again! A remarkable piece of polar engineering at work!

The Orbcomm transmitter spoke! Matt's lashed together ground plane aerial actually did pick up a signal with Matt running around with it held on a stick as high as possible when the satellite was at its near point to us. A test email message did get out directly from the AASTO without going via the internet! Not that we've quite got the system to a useful data transmission rate, but its a start in making the AASTO independent of the need to have a local ethernet available with which to communicate with it.

Daniel continues to investigate all kinds of weather conditions on the SODAR and write up the definitive works on its use in Polar conditions, as well as knock holes in the reliability of any wind measurements from meteorological balloons! The SODAR had developed a nasty squawk to one of its notes, but, as mysteriously as it occurred, it seems to have cleared up.

I've been continuing to play around with the data reduction software, getting around to looking at some of the code that hopefully will be used for our data reduction pipeline. This is a little different to the code I've been using, and I've been wanting to compare methodologies and results. Somewhat to my surprise inside an elegant package I've found a number of simple errors which rather mess things up as regards to getting results! But I guess that's life when you're
dealing with software!

That's all for now!

Michael B

 

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