A direct-view handheld binocular spectrometer for use in a variety of
educational settings. The device comprises a holographic transmission
diffraction grating and a uniquely curved quantitative wavelength scale
for viewing visible-wavelength spectra with both eyes simultaneously. A
variable width entrance slit, adjustable illumination for the wavelength
scale, and attachable corrective lenses enhance the ease of use and
efficiency as compared to traditional monocular spectrometers.