  MAPS, MMT Adaptive optics exoPlanet characterization System, is the upgrade
of legacy 6.5m MMT adaptive optics system. It is an NSF MSIP-funded project
that includes (i) refurbishing of the MMT Adaptive Secondary Mirror (ASM), (ii)
new high sensitive and high spatial order visible and near-infrared pyramid
wavefront sensors, and (iii) the upgrade of Arizona Infrared Imager and Echelle
Spectrograph (ARIES) and MMT high Precision Imaging Polarimeter (MMTPol)
science cameras. This paper will present the design and development of the
visible pyramid wavefront sensor. This system consists of an acquisition
camera, a fast-steering tip-tilt modulation mirror, a double pyramid, a pupil
imaging triplet lens, and a low noise and high-speed frame rate based CCID75
camera. We will report on hardware and software and present the laboratory
characterization results of the individual subsystems, and outline the on-sky
commissioning plan.
