WIYN Observatory


Hydra is a multi-fiber positioner that places optical fibers at the telescope focal plane corresponding to precise object positions on the sky. The light from each fiber is then transmitted to the Bench Spectrograph.

Hydra Overview

Full Unvignetted Field Size 60 arc-minutes diameter
Minimum Fiber to Fiber Separation 37 arc-seconds
Positioning Accuracy 0.3 arc-seconds (30m) rms measured
Configuration Time (100 fibers) 20-25 minutes
Number of Guide Fibers (FOPs) 10 (two of the 12 now broken)
Number of Available Science Cables 2
Number of Active Fibers Per Cable 90 Red1, 83 Blue1
Blue Cable Spectral Window2 3000 Å - 8000 Å3
Blue Cable Fiber Diameter 3.1 arc-seconds (310um)
Red Cable Spectral Window2 4000 Å - 11,000 Å
Red Cable Fiber Diameter 2.0 arc-seconds (200um)
Typical Throughput Value 1130 e-/s per Å, 5800 Å, 600@10.1 grating, blue cable, for V=10
Hydra Assignment Program whydra (Included in the Hydra simulator package)

NSF University of Wisconsin Indiana University Purdue University Pennsylvania State University Princeton University

Last modified: 07-Mar-2022 12:59:41 MST