Among the PFS instruments, “Cobra” modules position fibers to galaxies and stars on the Subaru Prime Focal plane. 42 Cobra modules, each of which consists of 57 fibers and its positioners, cover the entire PFS field of view without any inaccessible gaps as shown in Figure 1.
Figure 1: Arrangement of Cobra Modules. 42 modules are paved to cover the hexagonal field of view. Module in thick blue was already shipped to Taiwan, and ones in thin blue were shipped this time.
図１：コブラモジュール配置の模式図。42台のモジュールを並べて六角形の視野をカバーします。濃い青色は輸送済のモジュール、薄い青色が今回台湾へ輸送されたモジュールです。
Two groups are collaborating to assemble “Cobra Modules”; Brazilian team responsible for fibers, and Caltech (USA) for actuators to move fibers.
Since the first Cobra Module was shipped to Taiwan, the two groups have been integrating several modules with optimizing its assembly procedure. In the end of January 2019, 5 modules (corresponding to the thin blue ones in Figure 1) were shipped to Taiwan.
(左) 梱包された5台のコブラモジュール (右) 輸送準備をしているカリフォルニア工科大学のグループ
In Taiwan, ASIAA (Academia Sinica Institute of Astronomy and Astrophysics) and their subcontractor have been not only testing the first Cobra module, but also integrating the Prime Focus Instrument. After receiving the five modules, they are going to install spare modules onto the optical bench first to consolidate the secure installation process. Then they will start installing the science (i.e. non-spare) modules to be used for actual observation.
