Sean Goebel (IfA) SAPHIRA deployment at SCExAO In this tech talk I will present some of the highlights of the deployment of the SAPHIRA detector array on the SCExAO instrument at Subaru Telescope. SAPHIRA is a 320x256 pixel avalanche photodiode detector array sensitive to 0.8-2.5 μm light and is intended for photon counting (the signal of an individual photon is less than the read noise) and high (~kHz) frame rates. SCExAO is a coronagraphic extreme adaptive optics instrument at Subaru used for high-contrast imaging of targets such as exoplanets and protoplanetary disks. It utilizes a 2000-element deformable mirror updating at 3.5 kHz to produce near-infrared Strehl ratios approaching 90%. Unlike GPI and SPHERE, SCExAO is continuously in development and frequently undergoes changes to take advantage of the latest technologies and techniques. In recent observing runs, we have 1) used SAPHIRA to conduct studies of the fast temporal evolution of the speckle halos surrounding diffraction-limited PSFs, 2) used it to iteratively null slowly-evolving speckles caused by static aberrations and diffraction within the optical train, and 3) put pyramid wavefront sensor optics in front of SAPHIRA to test the feasibility of using it for pupil-plane wavefront sensing at wavelengths nearer to those of the science instrument. I will also discuss future efforts involving SAPHIRA on the SCExAO instrument, including the development of the Pizza Box electronics for greatly improved readout rates, efforts to use SAPHIRA for on-sky nulling of quickly evolving speckles, and the potential to use it as the primary WFS detector on future ELTs.