A team has developed a method that simultaneously corrects spectral-line bending across all slits of a slit-recombination hyperspectral imager, an instrument operating with multiple viewing angles. The correction is applied jointly rather than treating each slit separately, improving the spectral precision of the system as a whole.

In multi-slit spectrographs, the curvature or tilt of spectral lines is a well-known problem: light entering through different positions of the slit shifts slightly on the focal plane, distorting the shape of the lines and complicating the accurate assignment of wavelengths. With multiple slits and multiple viewing angles, this effect accumulates and can limit the resolution and fidelity of the measurements.

The new approach tackles the correction globally, adjusting the line deformation of all slits simultaneously. This keeps the spectral coherence between the instrument's different channels, something especially relevant when combining data from different viewing angles.

The improvement is of interest for remote sensing and imaging spectroscopy applications, where precision in spectral calibration determines the quality of derived products. The simultaneous correction also simplifies downstream processing and reduces dependence on per-slit calibrations.