With small size and high resolution, custom SQUIGGLE motors enable JPL to create a large, densely packed optical fiber positioning array in the spectrograph for the Subaru telescope on Mauna Kea, Hawaii
NEW VIDEO shows the motion of the two-stage Cobra fiber positioner, consisting of two custom rotary piezo SQUIGGLE motors in a theta-phi configuration. Precision motion allows the open-loop system to quickly converge on its target position within 5 micrometers. Small size enables a densely packed array of more than 2,000 positioners to provide complete coverage of a wide area of the sky.
Victor, NY - Researchers at NASA Jet Propulsion Labs (JPL) have successfully tested a second-generation "Cobra" fiber positioner for astronomy, consisting of two rotary piezoelectric SQUIGGLE motors from New Scale Technologies. The second-generation design reduced the number of move iterations required to move an optical fiber to its target position for collecting astronomical data. Design improvements include modification of the hard stops to minimize friction and improve robustness. Details and test results were presented at the SPIE Astronomical Telescopes + Instrumentation conference in July in Amsterdam.
A new video of the second-generation Cobra fiber positioner in action is available at
The newly published results highlight JPL's ongoing development of a spectrograph for the Subaru telescope on Mauna Kea, Hawaii. The Prime Focus Spectrograph (PFS) will have 2,394 positioners, each comprising two SQUIGGLE motors in a theta-phi configuration, able to move an optical fiber to within 5 µm of its target position in six move iterations. The dense-packed hex array of positioners with overlapping patrol areas enables 100% coverage of a large area of the sky.
The ability to quickly move fibers to their target position increases observing efficiency: less time spent positioning the fibers after each move of the telescope means that more time is available for data collection. According to the JPL paper:
"The current estimate is it takes 62 seconds to move the telescope and reacquire the new field of targets with 15 minute exposures. This will allow for approximately 45 fields to be observed per night. This will enable large scale surveys aimed at understanding dark energy as part of the Subaru Measurements of Images and Redshifts (SuMIRe) program... The Cobra system is a key aspect of PFS that will enable its unprecedented combination of high-multiplex factor and observing efficiency on the Subaru telescope."
The full paper (#8450-41) is available from SPIE at spie.org/x648.html?product_id=927161.
New Scale's piezoelectric motors met JPL's key requirements for the Cobra positioner:
· Small size, allowing more than 2,000 positioners to fit in a close-packed hex pattern with 8 mm center-to-center spacing
· High position resolution and the ability to quickly converge on a target position using open-loop positioning
· High torque to overcome the drag of the optical fiber as it twists during movements, and high holding torque to maintain the target position once reached
Initial work on the Cobra fiber positioning system was presented at the IEEE Aerospace Conference in 2009. See www.newscaletech.com/app-notes/cobra-jpl for further information.
About New Scale Technologies
New Scale Technologies develops small, precise and smart motion systems for critical adjustments of optics in imaging devices and many other micro positioning applications. Our simple and elegant solutions deliver best-in-class performance in consumer imaging, biometric authentication, surveillance, medical devices, scientific instruments, haptic systems and many other markets. We design and manufacture custom products and license our technology to manufacturers worldwide. Our customers benefit from complete motion solutions that are tailored to their unique requirements and easily integrated into their next-generation instruments.
Doug Camp, (585) 924-4450