An optical system for a high-resolution short-wave IR (SWIR) spectrograph to be employed in remote sensing applications is described. The instrument covers the spectral range from 1200 to 2400 nm and images a 9.4-deg line object onto a 2-D PtSi sensor. Spatial and spectral resolution requirements were set at 0.33 mrad and 10 nm, respectively. While signal strength calculations indicated that an aperture equivalent to f /1.8 would be adequate, because of the anticipated lower signal levels at the long-wavelength end, special attention was paid in the antireflection coating design stage to partially compensate for the large discrepancy in signal strengths found across the spectral range.