High-resolution imaging through strong atmospheric turbulence

Stuart Jefferies, Institute for Astronomy, University of Hawai'i

I will discuss how high-resolution imaging through strong atmospheric
turbulence is facilitated by maximizing the transmission of
information through the optical system and estimating the observed
wave front over a wide range of spatial frequencies. I'll show that
both requirements can be met by observing with a dual channel system
where one channel employs aperture diversity and the other an imaging
Shack-Hartmann wave-front sensor. The imagery from this setup is
processed using a blind restoration algorithm that combines the
strengths of the multi-aperture phase retrieval and multi-telescope,
multi-frame blind deconvolution techniques: it also captures the
inherent temporal correlations in the observed phases. This approach,
which strengthens the synergy between image acquisition and
post-processing, provides near-diffraction-limited imagery at
unprecedented levels of atmospheric turbulence (so strong you would
not normally contemplate acquiring data). The approach also allows for
the separation of the phase perturbations from different layers of the
atmosphere. This characteristic offers potential for a beacon-less
wave-front sensor and for the accurate restoration of images with
fields of view substantially larger than the isoplanatic angle.