A criterion for comparing spectral instruments is proposed, and some experi
mental results obtained using the MFS-1 Fourier spectroradiometer are prese
nted. A description of the novel MFS-B instrument package, which combines t
he functions of an infrared direction finder and a Fourier spectroradiomete
r employing a multielement detector, is given. (C) 2000 The Optical Society
of America.