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Up: Speckle masking interferometry

4. Conclusions

We have presented a method for interferometric imaging with the Large Binocular Telescope. The laboratory and computer experiments demonstrate that image reconstruction from LBT interferograms can easily be performed by the speckle masking method combined with the iterative building block method. The experimental results show the dependence of the reconstructed images on photon noise. The smallest simulated number of photoevents per interferogram was 200. This photoevent number corresponds to magnitude tex2html_wrap_inline1632 for two 8 m telescopes, 20 msec exposure time per interferogram, 5 nm filter bandwidth, and 10% quantum efficiency of detector plus optics. 200000 interferograms were evaluated per experiment corresponding to only 1.1 hours of data recording time for a frame rate of 50 frames per sec. The mean photometric error of the reconstructed stars of the tex2html_wrap_inline1634 star cluster is about 9.5% (for 200000 interferograms, tex2html_wrap_inline1636 = 40 cm, 200 photoevents/interferogram, only one spectral channel of 5 nm bandwidth). The simulated brightness of the individual four stars is 15.6, 15.8, 16.4, and 17.1. Objects of about 18th magnitude and fainter can be studied with 6 mas resolution if observing time is increased, data are simultaneously recorded in many spectral channels, and if partial wavefront compensation is achieved by an artificial laser guide star system.


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