Voyager results have shown that above the cloud at 1.0 bar methane is
undersaturated (Lindal et al. 1987). Since the stratosphere is heated
radiatively by 
absorption bands at 1.7, 2.3, & 3.3 
(Lunine 1993) this is the best regime to trace the methane in
the stratosphere and further constrain where the solar energy is
reflected or absorbed.
Assuming a seeing disk with GRIM of 1.3
(Gloria personal
communication) we have 2.8 resolution elements
across the diameter and 6.0 on the disk. The seven filters chosen are
a continuum band at 1.58 
, a
methane band at 1.70 
, a continuum band at 1.99 
,
two PIA bands at 2.122 and 2.248 
, and a filter at 2.36
which will also probe methane along with a K broadband
filter necessary to properly calibrate with the standard star. Figure
4 shows the level to which each wavelength band will probe. This is
defined as the level at which the optical depth for each band reaches
because the light we see traverses this path length twice.