Sparse Aperture Masking

My Bachelor research project on implementing Sparse Aperture Masking at the Leiden Old Observatory.

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In 2013 we designed and implemented a Michelson interferometry observing mode called Sparse Aperture Masking (SAM) or Non-Redundant Masking (NRM) at optical wavelengths on the student telescope located in the Westkoepel in the Leiden Old Observatory. The telescope was transformed into a seven-element interferometer using an aperture mask located in front of the primary mirror.

The manufactured aperture mask mounted on the student telescope in the Westkoepel at the Leiden Old Observatory. The alignment pins lock the orientation of the mask w.r.t. the telescope aperture.

Methods for designing this mask are discussed. A data-reduction pipeline was written in Python and the whole setup was validated using first-light observations of a 3 magnitude contrast binary at 1.5 λ/D separation.

The Chi-Squared map of the observed binary. The primary is located at the red cross. The lines indicate the 1, 2 and 3-sigma confidence levels.

Algorithms for creating Kolmogorov phase screens involved in simulations are also discussed. This involves

An example of a Kolmogorov phase screen generated by our algorithm. The lines indicate 2π phase shifts.