The AAO has six measuring machines for analysing photographic
plates and films. Two of these are located at the Epping
laboratory along with the archive of AAT prime focus plates, and
four are on Siding Spring mountain (two at the Schmidt telescope
and two at the AAT). Whilst all these machines can be used as
accurate XY measuring engines, only the PDS can be used to
digitize the plate and extract the density (intensity)
information. The PDS also yields the most accurate positions,
and should be used for determining target positions for AUTOFIB
from Schmidt plates. NOTE: The advent of large scanning machines
(eg. COSMOS and APM) and the publicly available catalogues they
have produced (eg COSMOS and APM southern sky catalogues, STScI
Guide Star Catalog and the STScI Digital Sky Survey) has meant
that the demand for scanning and position measurement at the AAO
has fallen off in recent years. The PDS is currently in-
operable, and there seems to be little community desire to
resurrect it. This Page Last updated: