Modern optical astronomy: technology and impact of interferometry

Abstract

The present 'state of the art' and the path to future progress in high spatial resolution imaging interferometry is reviewed. The review begins with a treatment of the fundamentals of stellar optical interferometry, the origin, properties, optical effects of turbulence in the Earth's atmosphere, the passive methods that are applied on a single telescope to overcome atmospheric image degradation such as speckle interferometry, and various other techniques. These topics include differential speckle interferometry, speckle spectroscopy and polarimetry, phase diversity, wavefront shearing interferometry, phase-closure methods, dark speckle imaging, as well as the limitations imposed by the detectors on the performance of speckle imaging. A brief account is given of the technological innovation of adaptive-optics (AO) to compensate such atmospheric effects on the image in real time. A major advancement involves the transition from single-aperture to the dilute-aperture interferometry using multiple telescopes. Therefore, the review deals with recent developments involving ground-based, and space-based optical arrays. Emphasis is placed on the problems specific to delay-lines, beam recombination, polarization, dispersion, fringe-tracking, bootstrapping, coherencing and cophasing, and recovery of the visibility functions. The role of AO in enhancing visibilities is also discussed. The applications of interferometry, such as imaging, astrometry, and nulling are described. The mathematical intricacies of the various 'post-detection' image-processing techniques are examined critically. The review concludes with a discussion of the astrophysical importance and the perspectives of interferometry.

Cramér–Rao sensitivity limits for astronomical instruments: implications for interferometer design

“…Detailed reviews of this field, which describe the scientific motivation and results, technical challenges and approaches, and existing and planned facilities and which contain extensive bibliographies, have been made recently. 1,2 Additional information is readily available.…”

Performance of a Novel PMMA Polymer Imaging Bundle for Field Acquisition and Wavefront Sensing

“…This application would work much better if the polymer used in the bundles is one that is efficient at wavelengths in the near/mid-infrared, such that extrasolar planet detection by imaging is feasible (Burrows 2005;Ireland 2012). Multi-object speckle imaging (Saha 2002) is also feasible with distributed polymer imaging bundles without fore-optics, again with all bundles feeding a sensitive high frame-rate camera off the focal plane. This would be useful in a fast survey to understand the fraction of multiple star systems (Duchêne & Kraus 2013).…”

Speckle Interferometric Technique for Astronomical Observations

“…By WienerKhintchine theorem. the inverse Fourier transform of equation (15) gives the autocorrelation of the object. (16) where, A stands for autocorrelation, Figure 7 depicts the autocorrelation of a binary star, HR4689.…”