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SEIMEI Telescope (Okayama Obs.)

3.8-meter SEIMEI Telescope was completed
Kyoto University Astronomical Observatory and Department of Astronomy completed installation of a new 3.8-meter diameter optical-infrared alt-azimuth mount telescope (now named Seimei Telescope) into the telescope dome on the summit area of Mt. Chikurinji (366 meter) in the southwest region of Okayama prefecture, between Asakuchi-city and Yakage-town. A press conference was held on August 17, 2018 to commemorate the completion of the dome structure.

The original development of a new telescope that resulted as Seimei Telescope began in the early 2000s. The construction of the dome structure began in 2016, and after three years Seimei Telescope achieved a great milestone with its mirror segments installed on the telescope itself in the summer of 2018.
Completed SEIMEI Telescope

Seimei is a distinguished telescope whose construction makes use of three techniques developed in-house.
First is the petal-shaped segmented mirror design for the primary mirror. The segmented mirror design is widely used by telescopes around the world, from the one of the largest ground-based telescopes 10-meter Keck twin telescopes (ref1) to recently the NASA/James Webb Space Telescope (to be launched on March 2021, ref2), and hexagon-shaped segment mirrors are typically used.
The primary mirror Seimei would be the world's first telescope with the primary mirror assembled from eighteen petal-shaped mirror segments. The optical characteristics of Seimei Telescope with the petal-shaped segments are supposed to be superior to telescopes with hexagon segments.

Second is the ultra-precision mirror grinding technology. It usually takes quite a long time and needs great cost to polish mirrors made from glass-ceramic material at high precision. For the case of the 8.2-meter primary mirror for Subaru Telescope of National Astronomical Observatory of Japan (ref3) at the summit of Mauna Kea, it took four years to complete primary mirror polishing (ref4). However, we successfully reduce the amount of time significantly, needed for shaping and polishing these mirror segments by incorporating our own ultra-precision mirror grinding technique.

Third is the light-weight telescope alt-azimuth mount. In order to observe the sky efficiently, Seimei Telescope needs to be able to point to any target objects within a very short amount of time. To do so, Seimei Telescope is built upon a light-weight but durable structural design. We were able to reduce the total weight of the telescope structure by adopting arc-like railings and truss structure to support the primary mirror segments and the telescope itself and optimizing the telescope design with a genetic algorithm.

Each of these technologies was developed specifically for Seimei Telescope on our own. Last but not least, the development of Seimei Telescope itself was also a significant task to achieve the project.

As of December 2018, we are giving final touches to the optical/mechanical/electronic sections of Seimei Telescope and fine-tuning the supporting software for telescope operations. We expect the first light of Seimei Telescope very soon, and the science operation will commence soon thereafter. Seimei Telescope will be one of the workhorses in 2020s astronomy. We look forward to making breakthroughs with our own Seimei Telescope.
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