A 500th Fibre Positioning Unit (FPU) was recently installed on the MOONS focal plate. This represents a significant moment as we are now halfway to completion of building up this remarkable forest of 1000 fibre positioners. The image below captures the growing collection of positioners in all their glory.
The rear of the plate has an understandably dense network of fibres and electrical connectors, these are arranged in three segments. This threefold symmetry is visible in pattern of the populated plate and explains why 50% completion doesn’t simply equate to one half of the plate being populated.
The keen-eyed will also spot a small, isolated cluster of 6 FPUs to the left of the main group. These are being used to put the path analysis routines through their paces. Another recent milestone is that some of the most complicated movement patterns we can dream up have been tested and successfully executed – without any collisions between the FPUs! You can see a video of this here.
And the very keen-eyed might think they spot gaps in the FPU forest, but these are actually the locations of acquisition cameras that peer out between the FPUs to precisely alignment the whole system up with bright starts in the night sky.