Having only a month or so left in 2020, the integration of the Prime Focus Instrument (PFS) is progressing in Taiwan. The integration and test of the PFI system are being carried out by ASIAA (Academia Sinica Institute of Astronomy and Astrophysics) and their partner institute ASRD of CSIST (Aeronautical Systems Research Division of Chung-Shan Institute of Science and Technology). Back in September this year, all the 42 fiber positioner (“Cobra”) modules have finally been installed on PFI successfully.
The 2400 fibers are routed inside PFI in the form of in total 84 tubes each of which contains about 30 fibers. These tubes are held and guided with the three custom-made parts called “modular plates“, so the tubes will not be tangled or twisted when the telescope attitude changes.
The 84 tubes are divided into 4 groups, and each of them is connected to a single spectrograph module. As presented in the photo below, different colors are given to the 4 groups of tubes for clarity. The fibers in each group are distributed over the focal plane more or less uniformly. This allows a single spectrograph module to observe the sky across the area of the focal plane. Meanwhile, this sets the integration sequence in such a way that all the Cobra modules should be installed first, and then the fiber cables need to be assembled after that.
Fiber cables inside PFI 
Fiber cables on the top of PFI
This final phase of fiber cable integration work is being carried out by the Brazilian team who are staying in Taiwan since October. So far 2 of the 4 groups have been successfully bundled as cables, and now the 3rd cable is being assembled. Once these fiber works are complete, the integration and test of the entire PFI system will be restarted and be getting into its last phase. To be prepared for this, the software development and the optimization of hardware integration processes are progressing in parallel to those fiber works.
