Six-Telescope Beam Instrument Shows Results in IR Interferometry, Astronomy

MIRC-X, the six-telescope beam combination instrument developed by the University of Exeter and the University of Michigan, together with C-RED One, a fast, low-noise, IR camera from First Light Imaging, are enabling new perspectives in IR interferometry for astronomy.

The MIRC-X imager is now looking at the sky on the CHARA telescope array, the world's highest-resolution imaging facility in IR light, located at the Mount Wilson Observatory in California. The new instrument combines the light from telescopes spaced up to 330 m apart. These characteristics make the CHARA array and the MIRC-X instrument ideally suited for imaging stellar surface structures or to image the environment around stars with unprecedented resolution.

The MIRC-X project is led by Stefan Kraus at the University of Exeter and John Monnier at the University of Michigan. It is funded by the European Research Council and builds upon earlier funding from the U.S. National Science Foundation. The project aims to image the discs around young stars for the first time with six-telescope IR interferometry. The discs constitute the leftover material from the star formation process and provide the stage where planets form. Once planets have formed, they shape the disc environment by carving out gaps or by stirring up the disc material in warps.

Spotting such structures in the inner disc regions requires an angular resolution far beyond the reach of conventional telescopes. MIRC-X and CHARA overcome this resolution barrier by combining the light from physically separated telescopes, achieving the image sharpness of a 330-m telescope. These new capabilities will enable astronomers to obtain high-fidelity images of protoplanetary disc, providing a glimpse on how our own solar system might have looked 4.6 billion years ago during its formation phase.

C-RED One is a scientific commercial camera developed by First Light Imaging, dedicated to SWIR imaging. It is based on the SAPHIRA e-APD detector, allowing avalanche amplification and multiplication of electrons. C-RED One's mechanics and electronics offer 3500 fps with a read-out noise <1 electron.

So far, the sensitivity of IR interferometric instruments has been limited primarily by the read-noise of the detectors that are used for recording the faint interference pattern formed by the starlight. The C-RED One's e-APD technology reduces these read-noise contributions by several orders of magnitudes, enabling MIRC-X to detect the faint interference pattern associated with protoplanetary discs.

The three-year development of the C-RED One has been funded by the European Commission in the frame of the Horizon 2020 SME Instrument program. In 2016, C-RED One was rewarded with a Prism Award for Photonics Innovation by Photonics Media and SPIE.