1.1 What Are The Advantages And Disadvantages of Multi-Slits?

Kitt Peak supports spectroscopic multiplexing with the fiber-positioner Hydra and Bench Spectrograph on the 3.5-m WIYN telescope (beginning in the Spring 1995 semester) and with multi-slit masks on the RC Spectrograph and Cryogenic Cameras at the 4-m. Which is better for your particular application?

• The advantages of multi-slits over Hydra are:

1. Closer spacing of objects. The closest spacing of objects with multi-slits is 3 arcsec (although this leads to very limited sky availability), while the closest spacing of Hydra at WIYN is 40.0 arcsecs.

2. Better sky subtraction in fields with variable background.

3. Higher throughput under many seeing conditions.

• The disadvantages of multi-slits over Hydra are:

1. Considerably smaller field (5.2 arcmin vs. 60 arcmin).

2. More limited number of objects (typically a dozen versus 70-80).

3. The fact that the wavelength range covered is a function of position within the focal plane.

4. Hydra fibers provide image scrambling, useful for precise radial velocity work.