We propose to observe 5 positions as listed in Tab. 1. Positions 1, 2, and 3 
are repeated observations of a dark field on the sky when the field is at 
68, 90, and 115 deg from the Sun, respectively. Pos. 2, 4, and 5 are located 
along the great circle at 90 deg from the Sun. The measurements will outline 
the large scale dependency of the ZL spectral shape on both solar elongation 
(Pos. 1,2,3) and ecliptic latitude (Pos. 2,4,5). Comparison of Pos. 1 with 
the spectrum taken in May 1996 will show the repeatibility of the spectrum 
9 months later. All sky positions are carefully pre-selected dark fields where
cirrus contamination is negligible.