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The Present and Future Status of Hydra (1Mar93)
(from KPNO, NOAO Newsletter No. 33, 1 March 1993)

Many improvements have recently been made on the user interface
software for the multi-object, fiber-fed spectrograph Hydra. The
primary feature is the implementation of an OpenWindows environment
that allows pan, zoom, and cursor readback capability in the graphics
display (which shows the locations of the fibers and target objects).
We have also completed the tools for hand assigning or modifying the
Hydra field configuration and for saving such modified configurations
into a Hydra format configuration file. It is now possible to assign
fibers to objects and random skies using the graphical display. We
stress that these improvements only work in the OpenWindows environment
and not in the older SunView implementation.

An updated version of the Hydra Users' Manual is soon to be released.
It will be available through the previously described ftp access or
through the Observing Support Office.

The original concept of the WIYN telescope included the implementation
of a wide-field, fiber-fed, multi-object spectrograph permanently
installed at one of the Nasmyth foci. Due to insufficient resources,
that instrument will be a reincarnation of the current Hydra, instead
of a second instrument.  As such, Hydra will be decommissioned from the
Mayall 4-m during the late spring of 1994. Commissioning of the
upgraded Hydra will take place during the summer and fall of 1994. We
hope to have the instrument back into the hands of visitors by the
spring of 1995.

The new Hydra will contain the same positioner, stages and basic
electronics.  However, a completely new focal plate will be constructed
to take advantage of the concentricity between the WIYN focal surface
and exit pupil, and to incorporate improvements which should eliminate
some of the residual fiber problems with the current instrument.  The
red fiber cable will be replaced with a new red cable containing fibers
with 200 m cores (corresponding to 2 arcsec in the WIYN focal plane).
The blue fiber cable will be preserved and moved over to the WIYN. The
fibers within the blue cable will subtend 3 arcsec in the WIYN focal
plane. The new focal plate will, in addition, be capable of accepting
additional fiber cables, allowing for future growth. The Bench
Spectrograph will move to WIYN without major modifications, except for
the ongoing effort to finish the spectrograph control software and the
high-throughput, all-transmission spectrograph camera.

Since the positioner itself will be virtually unchanged and since the
focal plate assembly is completely new, we should be able to minimize
the down time of the instrument to under 6 months.

Hydra users should start paying attention to Newsletter items regarding
the WIYN telescope scheduling as it is intended that the WIYN be
scheduled in a significantly different manner from the way other KPNO
telescopes have been scheduled in the past.

Sam Barden, Taft Armandroff

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