Help for PHOTFIT2_IRVINE

PURPOSE:

This is the sub-menu associated with Irvine's photometric
function. This function needs three input parameters and there absolute limits :
 EXPONENT,     IRV_EXP1,     IRV_EXP2.
 MIN_EXPONENT, MIN_IRV_EXP1, MIN_IRV_EXP2.
 MAX_EXPONENT, MAX_IRV_EXP1, MAX_IRV_EXP2.
 T_EXPONENT,   T_IRV_EXP1,   T_IRV_EXP2.
If a sulution guess falls out-of-bonds then the attemp will be aborted and 
a new guess attempted.




MATHEMATICAL BACKGROUND :

bidirectional reflectance [1/str] :

r(i,e,g)=( cos(i)*cos(e) )**EXPONENT) / cos(e) * (1-exp(-cos(i)*IRV_EXP1))/(1-exp(-cos(e)*IRV_EXP2))


REFERENCES :
old VICAR Photometry programs

PROGRAMMER:

Friedel Oschuetz
Institute of Planetary Exploration
DLR
12484 Berlin (FRG)