Left: Technical layout drawing of the PLM optical surfaces to scale. Note that the dichroic plate and the field stop are not shown as covered by the FoM1 in this view. Right: Schematic functional view: light enters from the top onto the primary mirror M1. The secondary mirror M2 can be moved in 3 degrees of freedom by the M2M to compensate launch and cool-down effects. Separated by a baffle, the light then enters the instrument cavity, where it gets relayed by two flat folding mirrors (FoM1, FoM2) whose coatings suppress photons below 0.5 μm. The tertiary mirror M3 directs the beam towards the dichroic plate. In transmission light enters NISP and in reflection VIS, by use of a third folding mirror (FoM3, silver coated). VIS consists of a separate FPA, an RSU, and a CU. Euclid’s FGS are co-mounted on the same structure as the VIS FPA. Figure credit: ADS.