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| South Pole Diaries 2000/01 |
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Sunday 10th
December 2000
From
John Storey.....
I awoke this morning at 5 am after
a strange dream in which I had just finishing giving a lecture
and started on question time. The first question was from
someone wanting to know how to write some complicated expression
in LaTeX. He was definitely asking the wrong person. While
trying to think up a plausible answer it suddenly occurred
to me why our instrument was recording a huge amount of noise
at one particular position of the mirror. It just had to be
that stepper motor again, oscillating back and forth about
its requested position and unable to settle down because we'd
turned off its holding current. All that we had to do was
to persuade it to be content with getting the position nearly
right, and to stop being so obsessive about the last decimal
place or two.
Sure enough, with this more laid-back
approach to life, the stepper motor has performed faultlessly
all day and all our data points are nice and clean.
Meanwhile Michael Ashley has come up
with some good ideas about the "Bored Eric" problem. These,
together with our own experimenting, mean that we can now
actually walk away from Summit for hours at a time and be
confident it is still recording the sky for us. Paolo has
written a macro called "nice_dreams" which allows us
to catch up some sleep while Summit goes about its business
of collecting data.
The remaining problem concerned the
ADC board that we had blown up on the very first day within
the first hour of switching Summit on. The only essential
function we had lost was the ability to turn the chopper motor
off under software control. This we had worked around by installing
a manual switch, and now all that could go wrong was the mains
power could fail in the middle of the night, switch back on
again, and cause Summit's chopper to fry itself. Power outages
are bound to occur, if only because the two diesel generators
are swapped over once a week. In the end we decided to leave
the faulty ADC board in place, and to rig up a magnetic switch
that would keep Summit switched off should the power fail.
This appears to work well, and means there is one less thing
for us to worry about.
We could replace the ADC card, as we
have a spare, but I am loath to do so. For one thing, we are
not well set up for the job and risk further static damage
to the PC/104 computer. Secondly the PC/104 computer hardware
is a stupid fiddly thing designed by ex-stepper-motor engineers.
Thirdly, it's sitting outside in the electronics rack where
the average daily temperature is around -33 C.
Today being Sunday we got on with a
few housekeeping jobs. I did my laundry, using one of those
amazing European washing machines that take about four hours
to wash a pair of socks, only to reduce them to their component
molecules during the spin-dry process.
 Sadly,
it was also time to organise my departure from Dome C. My
itinerary now is complicated by the fact that I will fly to
McMurdo as an Italian, metamorphose there into an American,
finally to revert to being an Australian once the NSF have
taken me by C130 to Christchurch. All this was negotiated
over the HF SSB radio, a process that involved using the powerful
Rohde & Schwarz transceiver with the crook antenna to talk,
and the weaker Motorola transceiver with the good antenna
to listen.
Chef Jean-Louis threw his all into
Sunday lunch, handsomely exceeding even the high expectations
of the station. It was the usual sort of affair: saumon fume
(smoked salmon)on crisp toast on a bed of fresh salad for
starters, followed by a pasta course of ravioli and then sauteed
NZ mussels with herbs accompanied by an excellent unwooded
Australian chardonnay. The main course was roast crocodile,
with a good Coonawarra cabernet/shiraz. Dessert was ile flottante,
which is a soft meringue floating in caramel sauce and drizzled
with toffee. The Berlucchi was, according to Paolo, not one
of the better vintages, but to my palate this Italian methode
Champenoise wine was perfectly acceptable complement to the
dessert. Lunch slowly wound down over a fresh fruit platter
with Kiwi fruit, assorted cheeses, individually made espresso
coffee and biscuits.
After lunch we checked the email and
decided to carry out some more tests. We took a break to watch
our colleagues, Jean-Michel and Karim, from the University
of Nice launch a weather balloon and radiosonde. They have
about 11 balloons, and their next flights will include microthermal
sensors to measure the turbulence of the atmosphere. Launching
the balloon invovles first inflating it with helium until
it can lift the 375 gram weight it is tied to---in this case
a can of VB beer. Next the batteries of the balloon payload
are activated by dunking them in water for a few minutes,
and finally the payload is swapped for the VB and away goes
the balloon. The signals from the payload are received in
the balloon-launch tent, and consist of jolly little tunes
not unlike the ones our sodar plays. The computer can then
interpret these as temperature, pressure humidity and wind
speed (which it gets from a little GPS).
After dinner I gave a science lecture
in the Free-time Tent, using poodle to drive a 20-inch monitor
(which was the biggest thing we could find). Being able to
use Powerpoint avoided the need for Paolo to do street theatre
and made for a colourful presentation. I think it went over
ok; at least no-one wandered off out the tent saying "I may
be some time..."
Around 10:30 pm we were taken on a
tour of the new station by Augusto Lori, the station leader.
The present station is really just a construction camp for
the permanent facility, which will consist of two 17 metre
diameter cylinders linked by a walkway. The cylinders will
be three stories high; one will be the "noisy" building
and one will be the "quiet" one. At the present moment
one cylinder has the frame almost finished, and the foot pads
for the second have been laid. Scheduled opening date is 2003,
after which time Dome C will be ready for year round operation.
John
 
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