Astronomers Focus “Robotic Eyes” on the Milky Way Galaxy

Thanks to an amazing robotic innovation, an international collaboration involving the Carnegie Institution for Science has developed the Sloan Digital Sky Survey (SDSS), a research project that has been investigating the structure and evolution of our cosmic home, the Milky Way.

A new focal plane system (FPS) called SDSS-V replaces a practical and time-consuming approach to simultaneous observations of hundreds of stars, which required astronomers to manually connect hundreds of optical fibers into holes drilled in a metal plate at the telescope's focal plane.

With this new innovation, the system's 500 automated positioning units replace human hands and precisely maneuver the optical fibers into place on the telescope's focal plane so that each can capture light from a specific star within the target region.

"We went from collecting a few thousand spectra each night to approximately 15 000", says Juna Kollmeier, director of SDSS-V, SDSS Phase 5, a researcher at the Carnegie Institution for Science and director of the Canadian Institute for Theoretical Astrophysics (CITA).

"It's a fascinating change in the way we work that will not only allow us to scan more objects, but also to examine these systems over time, on timescales we couldn't access before. This unlocks a lot of new science".

The development of the new robotic FPS was a five-year effort by an international team, including Ohio State University's Imaging Sciences Laboratory, the University of Washington, Ecole Polytechnique Fédérale de Lausanne (EPFL) and Carnegie Observatories in Pasadena.

The design teams have overcome many of the challenges posed by the global pandemic by developing and building components where they are located, some in their garages and backyards, and shipping them elsewhere for further assembly. The robots are manufactured in Switzerland and integrated into the main mechanical units in Columbus, Ohio.

Previous stages of SDSS observed millions of stars in our home galaxy using spectrometers, instruments capable of measuring starlight at different wavelengths. The resulting spectra reveal a wealth of information about the stars: their age, temperature, chemical composition, motion, and more.

There are two types of FPS units. One works on the Sloan Foundation's 2.5-meter telescope at Apache Point Observatory (APO) in New Mexico. A second unit is under construction and, when complete, will operate on the du Pont Telescope at Las Campanas Observatory.

FPS will enable two of the three basic science programs at SDSS-V: the Milky Way diagram (MWM) and the Black Hole (BHM). Together, these projects will gather data on millions of objects scattered across the sky, from stars in our galaxy's backyard to unimaginably distant supermassive black holes.

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