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SOPHOS is an aerostat-borne, sparsely filled 6-meter optical telescope that we plan to fly in Antartica. This paper presents the results of studies concerning the aperture configuration and the results of simulations of the imaging performance of the telescope.
We first describe the results of a computer optimization of the subapertures following a method proposed by T.~Cornwell, which consists of optimizing the coverage of the Fourier plane. When taking advantage of the earth's rotation (by taking exposures with the overall aperture rotated around the line of sight), the optimum configuration of subapertures is on a circle with unequal spacing. The effects of the spacing and diameter of the individual mirrors on the optical performance will be presented.
We then present the results of simulations in retrieving the observed object. When an object is observed at several roll angles, the point spread function is simply rotated at each roll angle and hence needs to be measured only once; it can be resampled for each observation. The images can be deconvolved using the Richardson-Lucy method, and it is possible to improve the images by deconvolving a set of images taken at different rolls using a single deconvoled image and a single (rotated) PSF. We will present examples of simulated image data, reconstructions in the presence of background and readout noise, and comparisons with images obtained with a filled-aperture telescope. We will also show the effects of imperfect cophasing of the subapertures on image reconstruction.
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