A general description of the instrument may be found in the Hydra/WIYN Users Manual, available on-line as an HTML document, via anonymous FTP, or from the KPNO Observing Support Office.
Hydra/Bench Characteristics at WIYN
|--------------------------------------------------------------------|
| Full unvignetted field | 60 arcmin |
| diameters | |
|-------------------------------|------------------------------------|
| Fiber diameters | 3 arcsec (blue fibers) |
| | 2 arcsec (red fibers) |
|-------------------------------|------------------------------------|
| Fibers available | 96 blue fibers |
| | 96 red fibers |
| | 12 field orientation probes |
| | 84 locations for future fibers|
|-------------------------------|------------------------------------|
| Minimum fiber separation | 37 arcsec |
|-------------------------------|------------------------------------|
| Configuration time | 20-25 minutes |
|-------------------------------|------------------------------------|
| Measured positioning | 0.33 arcsec (30 um) |
| accuracy | |
|--------------------------------------------------------------------|
|--------------------------------------------------------------------|
| Grating | 316 line/mm, blaze angle 7 d |
| | 400 line/mm, blaze angle 4.2 d |
| | 600 line/mm, blaze angle 13.9 d |
| | 860 line/mm, blaze angle 30.9 d |
| | 1200 line/mm, blaze angle 21.1 d |
| | 316 line/mm echelle, blaze angle 63.4 d |
|--------------|-----------------------------------------------------|
| Cameras | Red: (all-refractive 285mm focal length bench cam.)|
| | Blue: Simmons camera (381 mm focal length) |
|--------------|-----------------------------------------------------|
| Collimators | 6 inch f/6.7 paraboloid |
|--------------|-----------------------------------------------------|
| Detector | 2048 x 2048 thinned Tektronix CCD (24 um pixels) |
|--------------------------------------------------------------------|
More detailed information, including grating efficiency curves, can be found in the Hydra/WIYN User's Guide. Information about the red camera is available on-line. Queries about this camera should be directed to Taft Armandroff (tarmandroff@noao.edu).
A setup program is also available for defining the spectrograph configuration and planning observations. The setup program is available via anonymous FTP. PLEASE NOTE: For spectroscopic orders greater than 1, the setup program underestimates the exposure time by about a factor of 2.
MOS/Hydra proposers should keep the following queue observing default operation and calibration procedures in mind when filling out their proposals.
(1) The default mode of operation for the Bench Spectrograph CCD will be to read out the entire CCD with no on-chip binning at the default gain of 1.7 electrons/ADU.
(2) The number of spectrograph grating and camera configurations per night will be constrained as follows: (a) we will not change cameras at night; (b) we may change gratings but not between the echelle and some other grating; and (c) we may change the grating tilt.
(3) We will observe objects at airmasses of 1.5 or less unless: (a) advised that observations at higher airmass are acceptable; and (b) the objects never get above 1.5 airmasses.
(4) All target fields within your program will be assumed to have equal priority UNLESS you specify otherwise in the "Comments".
(1) We will take 9 full bias frames at the start of each night.
(2) Comparison lamp exposures will be taken before and after a series of program exposures on a given night with a specific fiber Hydra configuration.
(3) Dome flat exposures will be taken at least once per fiber Hydra configuration. A minimum of three flats will be obtained.
(4) In addition, we will observe spectrophotometric, radial velocity, and other user-specified standards as requested. However, these will be considered part of the approved program and must fit within the allocated time. See observing overheads discussion.
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Last Updated: 8/2/99, wiynq@noao.edu