High resolution imaging of astronomical objects

19th December 2023

Sheryl Miles

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Optical Surfaces reports that it has received a follow-up order from Magdalena Ridge Observatory (MRO) to produce three second generation off-axis beam compressors to expand the capabilities of the facility’s optical interferometer.

The Magdalena Ridge Observatory Interferometer (MROI) project’s mission is to develop a ten-element imaging interferometer to operate at wavelengths between 0.6 and 2.4 microns with baselines from 7.8 to 340 meters. The technical and scientific goals of the interferometer are to produce model-independent images of faint and complex astronomical targets at resolutions over 100 times that of the Hubble Space Telescope.

Dr Michelle Creech Eakman, Professor of Physics at MRO, commented: “To minimise diffraction effects from long distance propagation, the original 7.5x off-axis beam compressor supplied by Optical Surfaces was designed to allow a 95mm beam of starlight to be reduced in size for the final division among instruments on the telescope. Because of the excellent performance of this optical system, we decided to single source from Optical Surfaces Ltd for three second-generation beam compressors that offer a better field-of-view to aid interferometric alignment. These beam compressors will be crucial components in the MROI as they will allow us to work in the smaller beam space (less than 20mm diameter) outside the vacuum system. We are hoping to attain first fringes during the first half of 2024.”

Dr Aris Kouris, Sales Director at Optical Surfaces Ltd, added: “Located at 10,600 ft above sea level in the Magdalena Mountains, our beam compressors for the MROI are subject to considerable variation in temperature. This necessitates that we incorporate invar element tie bars in the beam compressor design to provide thermal stabilisation. Our beam compressors incorporate high-precision off-axis mirrors, which provide an unobstructed output and highly efficient transmission. Beam compressors are the optical tool of choice for decreasing the diameter of a collimated input beam to a smaller collimated output beam. The reflective design of our beam reducers is achromatic and with protected silver coatings can operate from the visible spectrum to far IR without adjustment.”