New Scale Technologies
Victor, NY
www.newscaletech.com

Exploring the final frontier has been a decades-long mission for many. Yet, the nature of space, such as limits of galaxy formation and galaxies’ gas cycles, is still unknown.

ViaSpec Integration of 600 Viper positioners in the telescope focal plane (Image: Via Project)

Exploring dark matter in the universe has been difficult in the past because it eludes direct detection. While much of the research dollars and public attention has been directed to space telescopes in recent years, the Via Project utilizes ground-based MMT and Magellan telescopes to create a high-resolution map to understand the motion of the stars and gas in the Milky Way, beyond the precision and scope of current astronomical instrumentation.

Via Project engineers, project managers and scientists from Carnegie Observations, Harvard & Smithsonian, and Stanford University are collaborating to build advanced spectrographs for use at the MMT Observatory in Arizona and Magellan/Clay telescope in Chile, which will be used in a five-year survey targeting stellar streams and dwarf galaxy candidates, as well as mapping large contiguous areas of the sky.

The ViaSpec is the all-star instrument for this mission. Collecting light from up to 600 individual targets, the instrument uses optical fibers to direct light into its spectrograph. In doing this, it will deliver 100 M/S radial velocity resolution for millions of stars. The ViaSpec instrument consists of fiber positioners, attached to a primary mirror cell, a 25m run of optical fibers from the positioners to the spectrograph. In collaboration with the Via Project Team, New Scale Technologies is manufacturing next generation “Viper” robotic fiber positioners to enable simpler yet faster survey operations.

The focal plane system hosts 600 Viper positioners, each moving an optical fiber. These robots and fibers are vertically oriented in the focal plane, allowing simultaneous positioning of all fibers to match unique star fields with a high fault tolerance. The optical fibers guide individual starlight to the ViaSpec spectrograph on a controlled-radius cable carrier’s neutral axis.

The bench spectrograph is a 260-mm beam spectrograph that accommodates 600 fibers located in a gravity-invariant, thermally stable enclosure. With a uniformly high efficiency of 90 percent, the instrument employs a binary grating, spanning the spectral region between the Mgb triplet and the NaD doublet. A high-quality image on a single large-frame CCD can also be produced through the camera, which has six optical elements.

New Scale is assisting with this effort through providing Viper fiber positioners. Viper positioners provide improved accuracy, simplified integration, faster star-to-fiber alignment, and accelerated data collection to speed the research.

Viper robots improve accuracy through a two-axis (Theta-Phi) rotation of each fiber that provides full fiber coverage of a patrol radius of 15.3-mm closed-loop positioning thru the Viper patrol radius is made possible using: (1) absolute angle sensors on each axis; (2) direct-drive piezoelectric SQUIGGLE motors, providing high torque with zero backlash, zero-power hold, and no gears; and (3) co-located drive electronics below each Viper robot with embedded closed-loop digital control and calibration.

The Viper fiber positioning module builds upon its predecessor, the Cobra fiber positioner that is used in the Prime Focus Spectrograph (PFS) for the Subaru Telescope. Cobra has a patrol radius of 4.75 mm. The larger patrol radius of the Via system allows embedded absolute angle sensing, control, and calibration. Each Viper robot is factory-calibrated with its embedded electronics to create a modular subsystem. The electronics are located below the Viper robot and fit inside the area of the patrol radius. Each Viper system is individually installed and removed from the focal plane.

Compared to Cobra, fiber-to-star alignment is faster, with fewer iterations, and requires less frequent use of the global fiducial camera. Local closed-loop positioning results in less time used for set-up and more time available for light collection.

The survey is expected to begin in early 2027, running for five years, 150 nights per year, and encompassing 3 million spectra. The Via project is planning for its data to build on the enabling data released by Gaia DR4 and LSST.

“This new Viper positioner reflects the best capabilities of our mechatronic technologies and team,” said David Henderson, Founder and CEO at New Scale. “We are combining our newest generation of motors, sensors, electronics, and software to achieve the most demanding science objectives of the Via Project.”

“The absolute positioning accuracy provided by the Viper robots will enable much simpler and faster survey operations, which is an exciting possibility for us,” said Charlie Conroy, Via Project Co-PI and Professor of Astronomy at Harvard University.

This article was contributed by New Scale Technologies (Victor, NY). For more information, visit here  .