Bird House

[Thomas Droege <tdroege2@earthlink.net>]

Good progress is being made on the bird house.  The roof is done, and one
roof section has been mounted on the slides and it looks like everything is
going to work as designed.  Late summer should have 4 more telescopes in
operation.  

There is always something to fix.  TOM2 somehow tied it's two thermometers
together.  This messed up the temperature control system.  At least it did
not read out correctly though it may have been working.  It is now fixed. 
All those good tested boards by the test stand are good for something. 
Little matter.  It is clouds, clouds, clouds.  

I am working on something called DeCam at Fermilab.  It is about a 500
Megapixel camera.  There is always a question of where to put the
electronics.  The current design has two big electronics crates wrapped
around the camera at the prime focus.  Everyone worries about what this
will do to the seeing.  We will probably have to cool the crates so that
they give off no net heat. Then everyone will worry about the cooling
anti-freeze leaking on the mirror.  There is no end to possible worry.  I
am thinking about bringing the camera signals down on a big cable instead
of processing them at the camera. This is something that will terrify the
others on the project.  It worries me too.  

 To test that this might work, I took one of the TOM3 cameras and put 137'
of cable between the camera and the electronics.  About all that I thought
the timing would stand.  The resulting images looked just fine.  I could
see stars through last night's clouds.  It was slightly noisier than with
the short cable, but it worked, and one could probably not see a
statistical problem.  I used an assortment of flat and round cables to get
the length.  A proper shielded twisted pair cable should work much better. 
This just shows  that dual slope integration double correlated sampling is
a powerful a technique

Tom Droege

Tom  Droege Jennifer Malpass
tdroege2@earthlink.net