The systems, apparatuses, and methods herein can provide a multi-site positioning mechanism suitable for long-term testing of a device(s) under test (DUT) (e.g. semiconductor wafers) across a range of temperatures with or without a controlled environment. The systems, apparatuses, and methods herein include mounting components, mechanisms, and structures that can provide excellent mechanical stability, permit relatively close working distance optics with high resolution, enable fine positioning at elevated temperature in a controlled environment with minimal thermal perturbation. The systems, apparatuses, and methods herein can be provided with modularity, for example as modular with rails and test sites that can be easily added or removed, and that can permit access to probe modules in a densely packed array.