The 3.8m Anglo Australian Telescope Two Degree Field (2dF) instrument can
acquire the spectra of 400 objects simultaneously and was used to complete a
redshift survey of 250,000 galaxies. Whilst one set of spectra are being
acquired at one end of the instrument, a robotic positioner prepares the
placement of optical fibers at the other end for the next set of observations.
When acquisition of one field is complete, the instrument has an automated tumbler
that allows it to rotate itself so the next acquisition can begin.
When built in Sydney the 1990's, it was the most complex instrument that had ever been
attached to a telescope.
The User Manual is available online here at the AAO web site -
http://www.aao.gov.au/2df/2df_old/ma...df_manual.html