The Prime Focus Spectrograph (PFS) is a wide field multi-fiber spectrograph using the prime focus of the Subaru
telescope, which is capable of observing up to 2400 astronomical objects simultaneously.
The instrument control software will manage the observation procedure communicating with subsystems
such as the fiber positioner "COBRA", the metrology camera system, and the spectrograph and camera systems.
Before an exposure starts, the instrument control system needs to access to a database where target lists provided
by observers are stored in advance, and accurately position fibers onto astronomical targets as requested therein.
This fiber positioning will be carried out interacting with the metrology system which measures the fiber positions.
In parallel, the control system can issue a command to point the telescope to the target position and to rotate
the instrument rotator. Finally the telescope pointing and the rotator angle will be checked by imaging bright
stars and checking their positions on the auto-guide and acquisition cameras. After the exposure finishes, the
data are collected from the detector systems and are finalized as FITS files to archive with necessary information.
The observation preparation software is required, given target lists and a sequence of observation, to find
optimal fiber allocations with maximizing the number of guide stars. To carry out these operations efficiently,
the control system will be integrated seamlessly with a database system which will store information necessary
for observation execution such as fiber configurations.
In this article, the conceptual system design of the observation preparation software and the instrument
control software will be presented.