In a skydip, the atmospheric emission, as seen by the receiver (
), is
measured at equally spaced airmass (
).
is a combination of
the atmospheric emission
and of losses
Assuming that
and
are independent of the elevation and
that
and
are correctly modeled by an atmospheric model,
we obtain that
is a function of
,
,
,
and the airmass (
). If
and
are assumed to be
measured by other means, then
and
can be fitted through
the measured couples (
,
).