Mounted directly to Discovery Hybrid Rheometer, Modular Microscope Accessory (MMA) enables simultaneous high-resolution optical microscopy with precise control and measurement of flow. Counter-rotating stage operates in conjunction with rotating upper plate to establish stagnation plane which aids qualitative and quantitative image analysis. System provides temperature-controlled microscopy at magnifications up to 100X and may be operated in bright field, fluorescent, or polarized light.