From: mar@physics.su.OZ.AU (David Mar)
Subject: DM's telescope postcard - 2
Organization: School of Physics, University of Sydney, Australia
Date: Wed, 26 Aug 1992 19:39:46 GMT

Mike Callahan calls for attention. "I have another postcard from DM here. 
Anyone who wants to listen, gather around." He waits until the interested 
patrons seat themselves, then reads:

Wednesday, 26 August

G'day Mike, Patrons,

16:00 - With an hour to go before dinner, things are happening apace here
in the AAT control room. I have spent much of the afternoon setting up the
spectrograph with the help of Jason, one of the support astronomers. We
have to adjust various things and fiddle with lots of little dials and
buttons in order to get things working properly. Then we run checks using
the computers to make sure that everything is working as expected.
Unfortunately the spectrograph appears to be slightly out of focus. Jason
and a technician are working on the problem as I write. 

I stayed up last night until just after 2am, when I was simply too tired to 
stay awake. I planned to sleep as long as possible, but body-clocks are 
marvellous things in that they wake you up at your normal rising time even 
when you _should_ sleep in... 

After dozing fitfully for another few hours, I rose at about 10 and
wandered over to the Visitor's Centre. This is a building near the AAT
building which caters to the many visitors who come up here to have a look
around. It contains a coffee and souvenir shop, and a quite impressive set
of astronomy displays. Visitors can also walk up to the AAT itself and have
a look at the telescope inside the building. The AAT building is split into 
two parts: the public accessible bit and the rest of it. There are windows 
between the two areas so that the tourists can watch the technicians 
fiddling with the telescope. I bought some posters at the Visitor's Centre, 
something I've been meaning to do for ages.

Then I wandered in here to log in briefly before breakfast. Breakfast is 
always a hearty serving of cereal, eggs, bacon, toast and so on. Since then 
I've been up here with Jason and playing with the big toys.  :-)

The weather is always an important factor when doing optical observing. 
Last night was clear, but today doesn't look promising. At the moment it is 
overcast, with patchy low cloud showing high cirrus above, and what looks 
like rain activity blowing in from the west. Jason was joking at breakfast 
that I always manage to bring bad weather to the mountain - I have a worse 
than average record so far for being clouded out up here. Now he is not so 
jocular about it, since the cloud has thickened and tonight looks like 
being a washout. Nevertheless, we must have everything up and running 
properly, in case the weather suddenly clears up, and we must remain alert 
all through the night for any signs that it is doing so.

18:42 - After dinner and after sunset. The end of astronomical twilight 
occurs at 19:05 tonight, which is when the sky is dark enough to get down 
to the real observing. Tonight is going to be even darker, since the clouds 
aren't likely to let any starlight through. The satellite photo of 
Australia, transferred here from James Cook Uni (Nicarra's old haunt), does 
not look good. Since we can't do any observing now, we are still trying to 
fix the spectrograph focus. It isn't too bad, after the afternoon's work, 
but our technician thinks he can get it better - and it's not as if we have 
anything else to do.

At the moment there are two other guys in here. One works for the 
observatory, and the other is a friend of his. Jason is showing them around 
and describing the various bits of machinery for the friend. The final 
person here right now is Jonathan, our night assistant. His job is to drive 
the telescope and make sure everything goes well all night. Jason is upset 
because he has bungled the weather. :-)

The way things work here is that the night assistant operates the
telescope, moving it to various positions on the sky, while the astronomers
(me!) work the computers and the detectors. But at times like this, there's 
not much to do except write postcards.

20:06 - Jason and I just went outside to check the weather. We actually saw 
a star! It was alpha Centauri - only the third brightest star in the sky. 
It was shining fitfully through the cloud. What chance to observe my 
quasar, some 15 million times fainter? (I have also changed from my shoes 
into slippers. Much more comfortable.)

23:34 - Things actually got a little better for a while there! Some stars 
came out and I latched on to one of the brighter ones for a couple of 
observations. All I use these bright stars for is to calibrate various bits 
of the quasar spectra I will take. The quasars are some tens of thousands 
of times fainter, and we couldn't find them through the cirrus cloud which 
is still floating around. Even the bright star's image wafted around the TV 
screen and faded from view every now and then because of the cloud. I also 
took some exposures of a thorium-argon lamp, which I will use later on to 
wavelength calibrate the spectra (using the known wavelengths of the lamp's 
spectral lines).

Then we had some time where we could see such bright objects, but not my 
quasars. So Jonathan decided to have a look at Saturn. We got its current 
coordinates from a computer program and steered the telescope there. There 
is a TV camera set up so that you can see what is coming in through the 
telescope, and the image of Saturn was quite amazing. I'd never seen Saturn 
"live" before, and I thought it was great. The planet was about five 
centimetres across on the TV screen, with its rings clearly visible and 
stretching about ten centimetres across. I even got a couple of printouts 
of the image to keep.

The man who was just looking around was also suitably impressed. And then 
we went down two floors to the telescope base, where the spectrograph I use 
is housed. Down there it is possible to stick your head in the path of the 
light beam and see the image. Not many people get to look through a 
telescope this big! That guy, his friend, and the technician have all left, 
leaving just me, Jason and Jonathan to mind the store.

And now the cloud has closed in again. There is nothing to do but sit 
around and wait for it to clear up. And listen to music on the CD player. 
:-)

Thursday, 27 August, 00:58 - Action!!! The clouds have cleared away and I 
am now observing a quasar!! Yay!!! The spectrum is coming in loud and clear 
as I watch. I take 3000 second runs (50 minutes), so there isn't much to do 
while the data collect. I spent the first twenty minutes of this first run 
eating some warmed up remnants of dinner (it's nicer than it sounds).

03:23 - Things are still going well. We are partway into the fourth run and 
the weather is still fine. We will try to continue observing this quasar 
until twilight begins at 05:04, then will observe some more bright stars 
until about 06:00, when the impending sunrise will make things impossible. 
After that, I get to go to bed!!!

05:34 - The night is drawing to an end. The sun rises in about 50 minutes, 
but the sky is already brightening. Also, some cirrus cloud has moved in. 
We observed the quasar up until twilightt, but the bright star observations 
will be useless for calibration as they are affected by cloud.

Now it just remains to set up a dark exposure of the spectrograph, to 
measure its noise characteristics. Then Jason and I can go to our rooms in 
the lodge and Jonathan can go home for a well-deserved sleep.

- Danger Mouse.
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