AbstractThe Japanese National Large Telescope is an 8-metre class optical-infrared reflector with a monolithic thin meniscus mirror, to be constructed at the Mauna Kea summit, Hawaii. The JNLT will be characterised by high quality performance in the optical and infrared regions, achieved by adopting new technologies such as active mirror support, fast optics and a thermally controlled dome. In particular, high infrared qualities are regarded as the most important characteristics among various design goals.The JNLT project is now close to the final study phase before construction. This paper reviews the scientific motivations and the special technical features of the JNLT. Finally, the promotion of international collaboration around the JNLT is emphasised.
We present details of design of elliptically bent Kirkpatrick-Baez mirrors developed and successfully used at the advanced light source for submicron focusing. A distinctive feature of the mirror design is an active temperature stabilization based on a Peltier element attached directly to the mirror body. The design and materials have been carefully optimized to provide high heat conductance between the mirror body and substrate. We describe the experimental procedures used when assembling and precisely shaping the mirrors, with special attention paid to laboratory testing of the mirror-temperature stabilization. For this purpose, the temperature dependence of the surface slope profile of a specially fabricated test mirror placed inside a temperature-controlled container was measured. We demonstrate that with active mirror-temperature stabilization, a change of the surrounding temperature by more than 3 K does not noticeably affect the mirror figure. Without temperature stabilization, the rms slope error is changed by approximately 1.5 μrad (primarily defocus) under the same conditions.
Programmable Active Mirror: A Scalable Decentralized Router