The Decaspec is an adaptor for multi-object spectroscopy with the MkIII spectrograph on the 2.4-m Hiltner telescope. It was constructed by Daniel Fabricant at CfA.

The Decaspec uses fibers with a projected diameter on the sky of 2.3" to take the light from the focal plane to the spectrograph. There are 10 fiber probes, each with 5 fibers arranged in a row across the width of a probe's track. The fibers are separated by 21.38 arc-seconds. The probe tip can be moved across the track width by +/- 0.0365 inches to allow an object to be placed on the nearest fiber. Each probe can be positioned along parallel tracks 23.4 arc-minutes long by 1.78 arc-minutes wide. A total of 0.115 square degrees is thus accessible.

This brief desciption is taken from the manual written by Daniel Fabricant, avaliable at MDM or upon request.