CZT Imager for AstroSat

The Cadmium Zinc Telluride Imager (CZTI) for AstroSat is a broad band hard X-ray detector with moderate imaging, good sensitivity, very good timing and polarisation capability. I will describe the design considerations and optimisation that have gone into the making of this instrument and highlight the methods employed to successfully surmount the challenges of making a high-quality space experiment. The major lessons learnt that could be used to make future Indian X-ray astronomy instruments are also discussed.