Results are reported from design studies of a fiber positioner and dedicated spectrographs for use in multiobject blue-UV spectroscopy at the new 2dF wide-field prime focus of the 3.9-m AAT. The technology of the present 64-fiber Autofib-1 system is being adapted to handle the 400 fibers and multiple spectrographs needed for the 2-deg unvignetted 2dF field; requirements include reconfiguration time 8 sec/fiber with iterative centroiding, position accuracy 0.2 arcsec (10 microns), button diameter 3 mm, and fiber probe freedom + or - 45 deg in theta and 75 percent diameter in R, with multiple crossovers. The spectrograph specifications include high throughput at 100-350 nm, spectral resolving power 5000 or less, efficient collimators, fast camera optics, and ability to resolve spatially all 400 fibers or subsets at different wavelengths and dispersions. Data from tests of fiber focal-ratio degradation are presented in graphs and discussed in detail.
|