Configuration of the DensePak array and sky fibers.
The "missing" fibers in the array have been damaged and are unusable
(fibers 36, 40, 46, 59, and 93). Please Note: DensePak is currently limited to time use only. In addition, 3 fibers have been damaged during the past 6 months and there are now a total of 5 unusable fibers in the array (see below).
DensePak is a fiber optic bundle that forms an array of 91 fibers in a 7x13 rectangle (see the accompanying figure). Each fiber is 300 microns in diameter which corresponds to 3 arcseconds on the sky at the Nasmyth focus of the WIYN telescope. Fiber-to-fiber spacing is 400 microns and the overall dimensions of the array are 30 arcsec x 45 arcsec. The array's orientation on the sky can be selected by setting the instrument rotator to the proper offset angle. Additional fibers are offset from the array corners and serve as sky fibers. The four sky fibers are located roughly 60 arcsec from the array center. The proximity of the sky fibers to the array may necessitate moving the telescope off target to properly sample the sky depending on the angular size of the target. Sky fibers have the same diameter as those in the array. DensePak's fibers have transmission characteristics similar to the Hydra "red" fiber cable. At present, two fibers in the array are unusable (fibers 46 and 59; fibers are numbered according to their slit position at the spectrograph). In addition, the throughput of several fibers at wavelengths < 4500-5000 Angstroms has been found to be substantially lower than that found for the majority of fibers in the array.
DensePak's fiber bundle feeds the WIYN Bench Spectrograph. Therefore, users have the same spectroscopic options for DensePak as offered for Hydra (see the Hydra Users Manual which can be found at http://www.noao.edu/kpno/manuals/hydraman/hydrawiynmanual.html).
Summary of DensePak/Bench Characteristics at WIYN
|-------------------------------|------------------------------------|
| Fiber array dimensions | 7 fibers x 13 fibers |
| | 30 arcsec x 45 arcsec |
|-------------------------------|------------------------------------|
| Fiber diameter | 3 arcsec |
|-------------------------------|------------------------------------|
| Fibers available | 86 "red" fibers - transmission|
| | characteristics similar to the|
| | red fiber cable used for Hydra|
| | 5 unusable fibers in the array|
| | 4 sky fibers |
|-------------------------------|------------------------------------|
| Fiber separation | 4 arcsec |
|-------------------------------|------------------------------------|
| Sky fiber location | 60 arcsec from array center |
|-------------------------------|------------------------------------|
|--------------------------------------------------------------------|
| 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) |
|--------------------------------------------------------------------|
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. This program is available via anonymous FTP. When running the spectrograph setup program, investigators should choose the blue cable to match the fiber diameter with that used in DensePak.
Configuration of the DensePak array and sky fibers.
The "missing" fibers in the array have been damaged and are unusable
(fibers 36, 40, 46, 59, and 93).
DensePak proposers should keep the following queue observing default operation and calibration procedures in mind when filling out their proposals.
DensePak will have a significant impact on the planning and operation of the WIYN Queue program because DensePak and the WIYN Imager use the same instrument port. Given the delicacy of the two instruments and the amount of time necessary for an instrument change, DensePak and the imager will not be swapped during nightly operations. To minimize conflict with the imager, DensePak is only offered for use during bright time.
The default mode of operation for the DensePak is the same as that described for MOS/Hydra (section 3.2.1).
The default calibration for DensePak is the same as for MOS/Hydra (section 3.2.2).
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Last Updated: 8/2/99, wiynq@noao.edu