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The Photon Simulator (PhoSim) is a set of extremely fast photon Monte Carlo codes used to calculate the physics of the atmosphere and a telescope & camera in order to simulate realistic optical/IR astronomical images. It does this using modern numerical techniques applied to the physical response of photons (and electrons) to comprehensive physical descriptions of the atmosphere, telescope, and camera. After these detailed physics calculations, PhoSim simply generates images by collecting electrons into pixels. This photon movie shows the photon Monte Carlo method used in the simulation where photons and electrons are physically propagated through the system using appropriate approximations. The physics of the site/telescope/camera includes: hydrodynamic-based descriptions of atmospheric turbulence, elasticity theory calculations of optical deformations, and electrostatic simulations of sensors. Since PhoSim is a physics-based code, it is written independent of the telescope/camera/site system, so there are a number of present and future observatories implemented as different input configuration files. Despite the physics detail, PhoSim is quite fast due to its novel efficient numerical implementation-- individual astrophysical objects can be simulated in milliseconds, and large fields of objects in minutes to hours depending on the size and depth. The links below describe how to use PhoSim, document detailed technical information about PhoSim, and show several example images.