In order to increase the swath width and reduce the volume of hyperspectral remote sensing instruments, the compact, long-slit Wynne-Offner spectrometers suitable for wide swath width were detailedly studied. By tracing the chief ray, expressions of the astigmatism were deduced, and the astigmatism of the Offner configuration and the Wynne-Offner configuration were analyzed. It was pointed out that the anastigmatic circle domain of the Wynne-Offner configuration is larger than that of the Offner configuration, and the former was more suitable for long slit. Two examples of spectrometers were given. Length of their slits are both 70 mm, and they worked in the wavelength range of 0.5~1.0 μm and 1.0~2.5 μm respectively. The imaging quality was close to the diffraction limit, and the spectral distortion was negligible. Such Wynne-Offner spectrometers have the advantages of long slit, compact structure and high imaging quality, and it is really suitable for the remote sensing applications with wide swath width.