At the request of the user's committee (see the March 1994 Newsletter), NOAO is in the process of fabricating a version of the Hydra multiobject spectroscopy fiber feed for use on the Blanco 4-meter telescope. A preliminary design review was held in December 1995, in which the project was endorsed and given a green light to proceed. Motors and electronics have been ordered. We are in the process of refining resource requirements and schedules to ensure that the project moves forward as timely as possible. The goal for delivery of the instrument to CTIO is during the second semester of 1998.
The instrument itself will look very similar to Hydra at WIYN. Upgrades in the motors, controllers, and stages will be implemented and should improve the positioning speed of Hydra/CTIO by a factor of 4 over Hydra at WIYN. We also plan to rework the software to modernize and better modularize the code.
The fibers will feed a renovated ARGUS spectrograph. All 288 fiber slots on Hydra will be utilized, allocated between two science cables with 138 object positions plus six guide probes per cable. The difference in the science cables will be aperture selection. A large aperture set (2") and a small aperture set (about 1.3") will be provided. The small apertures will take advantage of the image quality expected from a new wide field corrector. This will correct about a 50' field of view and will provide atmospheric dispersion compensation over that field. The corrector design also makes the telescope telecentric, allowing the instrument to utilize a warpable focal plate as is done at WIYN.
CTIO has started the construction of a new camera for the bench spectrograph to be used with this instrument, and has acquired a Tek2k CCD for use as the detector (see articles on Argus Update and CCD News in the March 1996 Newsletter). Modifications to the existing bench spectrograph and calibration system are planned at CTIO over the coming year.
Please stay tuned to future Newsletters for progress reports as this project proceeds.
Sam Barden, Tom Ingerson,
Bob Schommer, Nick Suntzeff