中国科学院南京天文光学技术研究所机构知识库

Our article “Optical system for extremely large spectroscopic survey telescope” has been accepted on December 26, 2023,  published online on March 7, 2024, and will be published in July 2024 Vol. 67 No. 7: 279511 in Sci. China-Phys. Mech.  Astron. In this article, a pure reflecting optical system with a novel strip lensm (lens-prism) atmospheric dispersion  corrector (S-ADC) is used, breaking through the glass material size limit of the lens atmospheric dispersion corrector,  making possibility to have an aperture of 16 meters and a field of view 2.5 degrees for the spectral survey telescope. This  paper gives a brief introduction to the previous article first, and then presents the progress of four important issues that  were not discussed in depth in the previous article: (1) The study of Integrated Field Unit (IFU) observation of the galaxy  extended sources in coudé focus; (2) The support structure and fabrication test of S-ADC; (3) A new special method of  optical fiber positioning unit to resolve the problem of chief ray not perpendicular to the focal plane. (4) The preliminary  telescope structure. Finally, this paper proposes to develop a spectroscopic survey telescope with a diameter of 14.5 meters.  Its Nasmyth focus with a focal ratio of 4 or 3.5, a field of view diameter of 2.5 degrees (or 2 degrees), equipped with about  50,000 optical fibers, is mainly used for spectral survey of point sources. The coudé focus is used for integrated field  spectral observation of extended sources (galaxies, etc.) with 4 arc-minutes and 2 arc-minutes field of view in diameter,  equipped with about 50,000 or even more optical fibers. We refer to this Telescope simply as ESST (Extremely large  Spectroscopic Survey Telescope).