After the arrival of metrology camera at the Subaru telescope…


Since we published the article about the delivery of the Metrology Camera System (MCS) to Subaru Telescope in May this year, the member mainly from ASIAA (Academia Sinica Institute of Astronomy and Astrophysics, Taiwan) have visited Subaru Telescope a few times, in order to finalize the integration and proceed the on-site tests. In this article, we are going to talk our work for MCS in the last three months.

MCS  is designed to acquire the spots of all 2400 fibers with uniform quality in one shot, in order to measure fibers position efficiently. After integrating a lens assembly shipped separately from the main system, we have aligned the optics to have uniform spots over the whole field of view. It is abut 18m distance between the MCS and Subaru prime focus. Therefore, in the dome building, ASIAA located pin-hole mask  and MCS in the equivalent distance , and adjusted position of the primary mirror and so on by looking the mask image.


Snapshot of alignment work by ASIAA. Locating MCS and pin-hole mask in the equivalent distance to real operation, ASIAA had checked image quality and aligned optics.

In June, MCS was installed to the Cassegrain focus to check mechanical interface with the telescope, and telescope balance with MCS. We also checked if the facility resources, such as power and network, necessary to operate MCS on-telescope are supplied in good shape. Software integration and command development have been proceeding to operate MCS via Subaru observation system.


MCS on Subaru Cassegrain focus at the on-site test

Now the rest is the engineering run, at which we will align MCS with respect to the prime focus on the telescope and test the effect of turbulence in the dome building. At the engineering run, we will install the pin-hole mask on the prime focus to demonstrate fiber spots at observation. In advance to  the run, we have tested the fitting with the prime focus unit, which we share with the current Subaru instrument Hyper Suprime-Cam (HSC).

  
Snapshots of fitting test of the pin-hole mask

We are also preparing required commands and tools for the engineering run.


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