Calibration on moonlit paper, lying on a carpet in the observing room 
of the N. Copernicus Obs. and Planetarium in Brno. There is a shadow
cast by the telescope tube on the floor. Wood-clad wall is on the left.

Moonlit part is 45 mnt in wide-angle frame, 50 mnt in the other one.
Shadow part is  10 mnt                  and 12 mnt.

Direct moonlight amounts to 35 to 38 mnt.

> 0.87*0.12/3.14
        ~.03324840764331210191
	
is the predicted value, for the given moment,
with some at least ten per cent uncertainty 
(20 cmag zenith extinctionn is assumed, as follows from the low-sun
illumination that afternoon, St. Nicholas 2003).

The agreement is within ten per cent, quite nice.