Simple and cheap hyperspectral imaging for astronomy (and more)

We propose a technique based on a transmission grating placed in front of an imaging system (e.g. a telescope) mounted on a frame that can be rotated around the optical axis. The grating creates, for each point of the source image (e.g. a star), at the focal plane, an image composed by the undistorted image of the star plus symmetrical dispersion images of several diffraction orders. The grating is rotated and several images are captured for different angular positions of the same. By analyzing the different images obtained for a different grating angle, it is possible to build the hyperspectral cube. The advantages of this method is its simplicity, extreme compactness and low cost making it suitable both for amateur astronomy and low budget science laboratory. We will present preliminary experimental results along with a discussion about the achievable spectral and spatial resolution and photon collection efficiency as a function of different type of gratings and of the number of the captured pictures. Furthermore, we present the result when the method is applied to extended non-punctiform light sources.