Developing engineering model Cobra fiber positioners for the Subaru Telescope’s prime focus spectrometer

Abstract

The Cobra fiber positioner is being developed by the California Institute of Technology (CIT) and the Jet Propulsion Laboratory (JPL) for the Prime Focus Spectrograph (PFS) instrument that will be installed at the Subaru Telescope on Mauna Kea, Hawaii. PFS is a fiber fed multi-object spectrometer that uses an array of Cobra fiber positioners to rapidly reconfigure 2394 optical fibers at the prime focus of the Subaru Telescope that are capable of positioning a fiber to within 5µm of a specified target location. A single Cobra fiber positioner measures 7. 7mm in diameter and is l 15mm tall. The Cobra fiber positioner uses two piezo-electric rotary motors to move a fiber optic anywhere in a 9.5mm diameter patrol area. In preparation for full-scale production of 2550 Cobra positioners an Engineering Model (EM) version was developed, built and tested to validate the design, reduce manufacturing costs, and improve system reliability. The EM leveraged the previously developed prototype versions of the Cobra fiber positioner. The requirements, design, assembly techniques, development testing, design qualification and performance evaluation of EM Cobra fiber positioners are described here. Also discussed is the use of the EM build and test campaign to validate the plans for full-scale production of2550 Cobra fiber positioners schedul ed to begin in late-2014.

Prime Focus Spectrograph (PFS) for the Subaru telescope: overview, recent progress, and future perspectives

“…5): After several years of prototyping and testing activities, 17 we recently started the mass production of the Cobras at New Scale Technologies. About 500 units have already been delivered as of Jun 2016.…”

Comparison of communication architectures for a fiber-positioning spectrograph

“…Therefore, no particular measure has to be considered to avoid the collisions. Others that have rigid parts 5,10 have to avoid the collision between adjacent positioners. Some solutions have reported that handling the movement speed would suffice for avoiding the collision.…”

Prime Focus Spectrograph for the Subaru telescope: massively multiplexed optical and near-infrared fiber spectrograph

“…PFS will accomplish the spectroscopic aspect of this project, and HSC has been implementing the imaging part since first light in 2012. : fiber system, 4-9 fiber positioner 10 and prime focus instrument, 11 spectrograph, [12][13][14] Dewar and detector, [15][16][17][18] and metrology camera. 3 PFS has now entered the construction phase, and Fig.…”