Authors

T. Kotani, K. Enya, T. Nakagawa, L. Abe, T. Miyata, S. Sako, T. Nakamura, K. Haze, Y. Tange

Affiliations

ISAS/JAXA; Université de Nice-Sophia Antipolis; Institute of Astrophysics, University of Tokyo; The Graduate University for Advanced Studies; EORC/JAXA

Abstract

We present the current status of the development of a cryogenic active optics for the SPICA coronagraph instrument (SCI). We have been developing a coronagraph instrument for SPICA, a 3-meter class infrared space observatory, which will be launched in 2018. The design and the development of two critical active components for SCI, i.e. a wavefront correction system with a MEMS deformable mirror and a tip-tilt mirror system will be described. A wavefront correction system consists of a 1024 element deformable mirror, which will enable us to achieve very high dynamic range imaging without extreme precision telescope mirrors. Our laboratory experiments at room temperatures showed that 10^6 dynamic range at 3.5 lambda/D was achieved with a stand-alone type binary mask thanks to wavefront correction with a deformable mirror. The wide-band experiment at visible wavelengths and a plan for the future cryogenic experiment will be present. We also show the designs of a cryogenic tip-tilt mirror system, which will allow a very precise, fast tip-tilt correction with extremely low heat-load. Several actuator systems are candidates for the tip-tilt system and the selection is ongoing based on the several criteria for example actuator strokes, heat generation, and compactness of the system.