Flexure test of Observation instrument was conducted with telescope simulator

In April 2011, a new laboratory building was constructed at the north side of the main building at Mitaka Campus of Institute of Astronomy, for the purposes of assembling and evaluating observation instruments which will be installed on the TAO telescope. The laboratory building consists of a large laboratory, a precision laboratory, and a remote control room. In the building, assembly, vacuuming/cooling tests, flexure tests of observation instruments have been conducted.

Telescope simulator on which SWIMS is mounted.

In this occasion, we have conducted a flexture test (tilt test) of the near-infrared instrument SWIMS using a telescope simulator installed in the large laboratory. This is to measure how the instrument warps and deforms when installed on a telescope focus, how the degree of the deformation is changed with the angle of elevation and rotation of the telescope, and finally how they affect the optical performance of the instrument.

The observation instrument for TAO weighs over 2 tons and have a complicated structure, making it difficult to predict precisely mechanical deformation only by simulation. Therefore, we need to confirm the deformation by actual measurements, and to reinforce the instrument if necessary.

Simulation Results of structural analysis (FEM analysis) of SWIMS (Provided by: Sumitomo Heavy Industries, Ltd.)

Two Flexure tests of SWIMS have been carried out in 2013 (August 23-24 and December 19-21). In the tests, the amount of the displacement from a fixed point was measured at several locations on the instrument using laser ranging devices by changing the tilting angle of the instrument. Comparing the measurement data with the structural analysis simulation, we have figured out how to optimize the instrument design, and now are performing improvement on the structure.
In the future, we plan to carry out further flexure test of SWIMS as a whole system in which all the components such as the multi-object spectroscopy unit are installed. In addition, a flexure test for MIMIZUKU, the mid-infrared instrument, will be scheduled in 2014.