Overview

NEWS:

Download the latest simulator (includes hydraassign):
              Solaris version -- Linux version (updated October 2001)

Latest hydraassign code binary (valid for 2010+, will be placed in the above tarballs) binary code
Replace this in /Hydra/bin/

Get the latest concentricities file:

• concentricities --for use with the 400m Bench Schmidt camera (November 2009).
• alternating_concentricities --for use with smaller numbers of targets or the Air Schmidt camera (emergency backup only, updated March 2000)
• translation table between fiber numbers and apertures.

(NB! Be sure that ECCENFILE in .fiborg points to the right concentricities file)

Hydra-CTIO

"Hydra-CTIO" is a multi-object, fiber-fed spectrograph which is used with the CTIO Blanco 4m telescope. The positioner is mounted at the Cassegrain focus, with the fibers feeding a bench spectrograph located in a room below the dome floor. Hydra-CTIO will ultimately be the principal Cassegrain instrument on the 4m telescope.

The instrument was commissioned during October-December, 1998. It was first used with an Air Schmidt camera and Loral CCD. In its current incarnation, Hydra-CTIO uses a 400mm camera and SITe 4Kx2K detector. The new camera/detector combination offers superior resolution and lower dark current compared to the old Air Schmidt. The Loral Air Schmidt is no longer in use.

Hydra-CTIO is similar to Hydra-WIYN, now in routine use at KPNO. A number of upgrades have been made to Hydra-CTIO. Its salient parameters can be summarized as follows:

• 138 large (300u/2.0" dia.) fibers
• Spectral coverage 330-1100nm
• Positioning time ~20 minutes (~8 sec./fiber)
• 40 arcminute field of view
• Minimum fiber-fiber distance 25"
• Atmospheric Dispersion Compensation
• Slit plates for higher spectral resolution: spectral resolution to ~50000 with the 400mm camera and the narrowest slit plates