The level of the Moon straylight is assessed during the solar eclipse period in
September-October 97. On three subsequent revolutions the telescope is pointed
at the same position of the sky, while the Moon is approaching from 50 to 
28 degrees. Influence of the solar straylight is suppressed by the eclipse.
Any measurable difference from the absolute sky brightness can be attributed to 
the Moon strayligth. In order to calibrate the signal absolutely  measurements 
on a celestial secondary standard are repeated on each revolution. At 170 micron
 
this is the galaxy ESO 486-G049.