Author ORCID Identifier

0000-0001-6311-8629

Date of Award

12-2024

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

First Advisor

Fabien Baron

Second Advisor

Stuart Jefferies

Abstract

Imaging objects in space is of interest to both astronomers and government agencies alike. Various government agencies are interested in maintaining situational awareness in the final frontier by direct monitoring of space-based assets. Monitoring man-made objects requires direct imaging techniques. However, corruption by the Earth’s atmosphere makes direct imaging more difficult. Techniques such as speckle imaging have been employed to “freeze” the atmosphere and recover the underlying object with high fidelity. State-of-the-art speckle imaging techniques, namely Multi-Frame Myopic Deconvolution (MFMD), rely on wavefront sensing to provide accurate Point-Spread Functions (PSFs) for recovery of the underlying object. First, we show successful recoveries of simulated scenes with spatially-varying PSFs. We show that, for fields once considered isoplanatic, there are considerable advantages to including anisoplanatic effects in the recovery process, such as improved accuracy on recovered flux ratios and improved object morphology. This allows for full atmospheric tomography and improves the fidelity of both on- and off-axis sources. Typically, speckle images are collected across a narrow bandpass. Here we also extend speckle imaging to a broad spectral range (Δλ ∼ 600 nm), i.e. hyperspectral speckle imaging, using numerical simulations of broadband speckle images. This brings with it vital gains in sensitivity and improved sampling of the wavefront from chromatic effects. From this, spectral information on the target is recovered, which could pave the way for future material aging studies. Finally, to complement these numerical studies we built a suite of optical experiments to simulate turbulence and simulate wavefront sensing instruments. We also develop and deploy the ARGOS 2-channel broadband imaging instrument on the Hard Labor Creek Observatory (HLCO) 0.7m telescope with limited success.

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