Microscopy is to our knowledge one of the only technological fields where the purchase of a microscope comes without instructions for maintenance, index of critical points, documented measured calibrations, maintenance assistance document. The 3M working group of the RTmfm wishes to propose open source methods, tools and protocols for measuring the health status of a photonic microscope in order to improve the performance monitoring of our systems. The quality control (QC) measures of a microscope are too often neglected for several reasons: lack of training of machine managers, affordable adapted tools, and human resources. These measures are however of primary necessity in the face of the growing need for repeatability experiments in biology and in front of the pressure exerted by scientific journals to deliver the raw data. Among these measurements, the most important in the life-time of a machine are those that were established at the installation. These parameters become the reference point on which the facilities engineers and technicians will create their future QC measurements . The GT3M thus offers 7 measurement points through simple protocols.