New approach to very-high-resolution astronomical imaging

Abstract

The Magdalena Ridge Observatory Interferometer will produce extremely sharp images of faint astrophysical targets while minimizing reflections and wavefront aberrations to maintain sensitivity.Astronomical objects are very distant, and so the angular sizes of many astrophysical phenomena are much smaller than can be resolved with conventional telescopes. Optical interferometry allows us to explore very small angular scales. Michelson and Pease first used interferometric observations nearly a century ago to measure the stellar diameter of Betelgeuse. 1 Since then, more than a dozen interferometers have been built worldwide to characterize the sizes and motions of stars and their environments. However, advances in technology have only recently allowed us to reconstruct physically realistic images of these objects rather than merely providing simple size measurements. We are ambitious in building the Magdalena Ridge Observatory Interferometer (MROI), with a mission centered on one primary goal: producing very-high-resolution images of faint astronomical targets. 2 Stellar interferometry works by combining the light from multiple telescopes to form interference fringes. This requires a complex optical system involving multiple light reflections from the light-collecting surfaces to the detectors measuring these fringes. Each reflection adds aberrations to the observed signal and results in photon loss. For other interferometers, often more than 40 reflections are required before the interference fringes are measured. The MROI design minimizes the number of reflections to only 21, allowing scientists to observe much fainter targets than previously accomplished. In addition, the interferometer design (see Figure 1) capitalizes on having small-diameter (1.4m) movable telescopes, so that the array can be reconfigured easily to match the resolution needed for observations of a particular target, much like the operation of our larger radio counterpart, the Very Large Array.

A Review of AGB Mass Loss Imaging Techniques

“…Because of this the source coverage in Fourier space is generally not sufficient to generate true images of the observed targets. The Magdalena Ridge Observatory Interferometer (MROI) in New Mexico is being built from the ground up to be an imaging interferometer (Creech-Eakman et al 2008). The MROI will operate in the optical and near-IR, in order to access key gas and dust diagnostic emission.…”

Post-Red Supergiants

“…Future VLTI data are planned to improve the uv coverage so that we can directly probe the geometry of the circumstellar material. The future is exciting, with imaging interferometers operating in the optical and near-infrared such as the Magdalena Ridge Observatory Interferometer becoming in operation soon (Creech-Eakman, 2008), we can begin to properly parametrize the winds of evolved stars.…”

Low-cost capacitive sensing for precision alignment of mirrors

“…The Magdalena Ridge Observatory Interferometer (MROI) [14,15] is our application for closed-loop control; it features a fast optical switchyard [16], which rearranges the beams of light from several telescopes before they are combined and measured. The switchyard works by moving mirrors along tracks, but these tracks are not perfectly straight due to manufacturing defects.…”