Re: [TASS] Flat fielding

[Chris Albertson <chrisja@jps.net>]

Andrew Bennett wrote:
>

> >You can't point it at a "dome flat" spot because it does not point.
>
> If the camera won't turn to point at the dome, the dome must turn
> to point at the camera.


There was talk on this list maybe a year or so ago about making
some "integrating spheres".  This is a big hollow ball painted
flat white inside (special white paint)  There is a hole for the
lens to look in and another to let in a point light source.  For
the Mk III the sphere needs to be about 18 inch diameter.
There was another type of flat target suggested that used multiple
defusing screens.
I don't think anyone actually built one of these devices.  Neither
would be expensive

--
   --Chris Albertson             home: chrisja@jps.net
     Redondo Beach, California   work: calbertson@logicon.com