Re: flatfield box

[droege@wwa.com]

Arne and all,

I sure would like to use a pulsed LED (or several colors) to drive
the light box.  One can get about 6 orders of magnitude range that
way by pulsing.  This is very hard to do with an incandescent bulb
which then needs neutral density filters and the like to adjust 
the intensity.  The whole mess can then be run from one 9 volt 
transistor battery and will last months.  

Tell me again why a monochromatic light source is so bad?  I suppose
because it might be sitting on the slope of the CCD response curve.
But what is going to move?  And for a flat field, do we care?

I too like Norman's design and plan to use it.  But with Tyvek as the
light screen.  We have not done all those measurements for Auger for
nothing.  Of course, most of the measurements were made under water.

Tom Droege

On Tue, 19 Aug 97, aah@nofs.navy.mil wrote:
>The article Glenn mentioned in CCD Astronomy has a side bar by Dave
>Petherick on his light box for his 8" telescope.  I think Norman's
>system is better designed, but Dave's system is simpler.  There
>are probably other designs out there somewhere on the net.  I'm sure
>Tom will come up with an elegant solution to the problem!  I'd like
>to see a flatfielding system that is cheap, works well and is easy to
>provide to all of the TASS sites.  Having the Tycho database is going
>to be an interesting check on how well these systems work!
>Arne
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