small progress at RIT

[Stupendous Man <richmond@a188-l009.rit.edu>]

  [Tom, I saw "Test #3", and am stimulated to emit this message]

  Over the weekend, I took the cameras off the Mark IV in Rochester
and noticed that the shutters don't quite close all the way.  It appears
to me to a function of the design -- there's a hard stop into which
the shutters move when they open, and the stop causes the shutters 
to slide slightly along the strings that drive them.  This displaces
the shutters from their proper position, leading to a small gap
between the leaves when they return to the "closed" position.

  So, I tried fixing it by constructing small flaps from black
construction paper and affixing them to one leaf of each camera's shutter.
The flap sticks out and over the edge of the leaf, far enough to cover
the gap between the leaves.  My second try at flaps appears to have
worked reasonably well.

  I need the flaps because I am going to do some flatfield tests
with light boxes built by one of my students.  Without good darks,
I can't make good flats.

  More when I manage to use the light boxes.  Mark Teseny built them
over Christmas vacation.  They look very nice, with adjustable lights
and several layers of diffuser.

                                               Michael Richmond