Next: acknowledgements
Up: A hierarchical phasing algorithm
Previous: Limiting magnitude
Our simulations of co-phasing algorithms, using a triplet
hierarchy, show convergence for both the cases of unresolved and
resolved objects. With 3 different wavelengths, zero path difference has
been achieved with initial errors of the order of .
Simulations with limited photon rates have shown that resolved images
of bright stars are in principle obtainable with apertures of 10cm, using
adaptive phasing at visible wavelengths. Arrays of large adaptive
telescopes should extend the limiting magnitudes towards mv =20 on
Earth and mv =35 in space.
Possible refinements of these algorithms remain to be explored, but the
simulations demonstrate the effectiveness of the triplet algorithm, used
with image sharpness criteria, for phasing a multi-aperture array. This
establishes the practical feasibility of obtaining high-resolution snapshot
images on compact objects, with future interferometers spanning up to
thousands of kilometers. In particular, it supports current projects
towards obtaining resolved images of exo-planets with sufficient quality
to see clouds, continents and vegetated areas ([Boccaletti et al. 1999]).
Ettore Pedretti
4/20/1999