is, therefore, dependent on the time of year and the direction of
observation. Leinert et al. (1998) have collated all observed values
of the zodiacal light as a function of helioecliptic coordinates
into a table, which we used in this tool. We assume that the zodiacal
light has a spectrum which follows the Sun. The module
CALC_ZOD_FLUX calculates the zodiacal light with inputs of the
name of the zodiacal distribution file, the time (hour, day, month,
year) and the WCS parameters, defined in the governing parameter
file diffuse_initparams.txt. The zodiacal light spectrum
is generated by scaling the solar spectrum as per the helioecliptic
coordinates of the line of sight using Leinert’s table (Leinert et al.,
1998). This spectrum is then convolved with instrument response
function to get the contribution of zodiacal light for a given direction
using the function CALC_SCALE_FACTOR. These steps are repeated
to estimate the value at each pixel in the FOV (or for the
whole sky). The output is stored in a two-dimensional array.