29th January 1994
From
Michael Burton.....
Well the weather's kept
up its show, apart from a brief interlude where
it all cleared up and the sun shined in a blue sky for a couple
of
hours. Visibility got down to 300-400m at times, the the trek
across
to the Astro building felt a bit like a real Antarctic expedition.
But
I think it does us good to have to wander out in these conditions
at
times - reminds us of exactly where we are. You can really
be a
bystander to the environment here if you work in the Dome
and always
take the Cats when out on the ice. To tell the truth the gear
we've
got is so good that you really only feel the chill around
the mouth
and nose. No planes arrived today. This weather would be no
problem
however for our balloon-borne telescope.............
A good day work-wise though; the IRPS
was put back together and the
motors turned! Some minor panics when I couldn't initially
calibrate
one wheel, and with the other slipping. But a simple offset
in the
software fixed one, and tightening a screw the other. Our
major
concern is of things overheating! The heaters that Michael's
installed really do their job, and in the lab we seemed to
be getting
into danger of melting the solder! We pumped on the vacuum
for the
first time in over two weeks, but its held really well, and
we are
hopeful we might not need to pump all winter. The molecular
sieve (the
'getter' as the Yanks call it) is really doing its job. I
played
around with the detector in the lab, and it seems to work,
and I took
some CVF spectra. The most frustrating thing is that there
is a minor
software bug that is preventing me from graphing the results
properly,
so I haven't seen what I've got so far, just imagined it from
the
numbers!
We have now to pump the inner to solid
N2, adjust the Fet Balance and
flash the detector - and then it can go outside on the roof.
I'm
hopeful we'll get around to that either today or tomorrow.
Incidentally the gold mirror we're
using to reflect radiation into the
dewar has now been outside on the roof, unprotected, for about
3
weeks, with absolutely no sign of deteriation or contamination.
Even
in the ice-drizzle we've had the past couple of days, nothing
sticks
to the surface of the mirror; it's simply too dry here. CARA
have done
some expts leaving out mirrors all winter and found the same,
so that
will make life easier in some respects.
The weekend is the time we can make
personal telephone calls, for the
5 hours or so when the GOES satellite is visible. It's imperative
to
be in the line to sign up early when the list goes up, otherwise
you
get stuck with the most undesirable times. I didn't know this
vital
bit of information, and am stuck with the 4am slot for my
calls!
You're expected to have an AT&T card to charge to as well,
so my
family is going to be paying for reverse charge calls from
the States!
Michael
Addendum from Michael Ashley:
The heaters I installed regulate the
temperature to +5C,
unless the dewar is inside in a cosy +20C environment,
in which case the stepper motor power is sufficient to raise
the temperature to +60C, which is about 100 degrees too
cold to melt solder :-)
 
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