The IACAT (IAC Atmosphere and Telescope) Simulator is an Optical Ground Support Equipment which simulates atmospheric turbulence and reproduces the performance of three very different telescopes: GTC and WHT, located at the Observatorio Del Roque de los Muchachos in La Palma (Canary Islands), and OGS which is located at the Observatorio Del Teide in Tenerife (Canary Islands). Its mission is to provide Scientists with the same measurement conditions as the real telescope but in a friendly laboratory environment, to assist in the development of new adaptive optics methods based on FPGAs. The most important telescope characteristics are simulated, such as f number, pupil size and position, magnification, central obscuration, etc. Up to 13 stellar objects can be created, individually or as binary stars with specific angular separations down to miliarcseconds. For the atmosphere simulation, it allows the creation of three different turbulence layers concurrently with different altitude and wind speed ranges.