4MOST fiber feed concept design

4MOST, the 4m Multi-Object Spectroscopic Telescope, features a 2.5 degree diameter field-of-view with ~2400 fibers in the focal plane that are configured by a fiber positioner based on the tilting spine principle (Echidna/FMOS) arranged in a hexagonal pattern. The fibers feed two types of spectrographs; ~1600 fibers go to two spectrographs with resolution R>5000 and ~800 fibers to a spectrograph with R>18,000. Part of the ongoing optimization of the fiber feed subsystem design includes early prototyping and testing of key components such as fiber connectors and fiber cable management. Performance data from this testing will be used in the 4MOST instrument simulator (TOAD) and 4MOST system design optimization. In this paper we give an overview of the current fiber feed subsystem design, simulations and prototyping plans.

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