Abstract Details

Name: Janani Varadhachari
Affiliation: Indian Institute of Astrophysics
Conference ID: ASI2020_535
Title : Primary Mirror error budget development for National Large Optical Telescope
Authors and Co-Authors : Sriram Sripadmanabhan, Janani Varadhachari, Gajendra Pandey, G.C.Anupama
Abstract Type : Poster
Abstract Category : Instrumentation and Techniques
Abstract : National Large Optical Telescope(NLOT) is India’s proposed future 10-meter class optical infrared telescope. NLOT follows Ritchey Chretien configuration with primary and secondary hyperboloid and a flat elliptical tertiary mirror at 45 degrees to the optical axis bringing the light to Nasmyth focus. NLOT is designed for a 10 arcmin un-vignetted field of view and gives a diffraction limited performance beyond 1mm wavelength. The primary mirror of the telescope consists of 60 hexagonal shape segments each of size 1.44m and a thickness of 45mm. Segments are grouped into six sectors with each sector having 10 segments with unique prescription. Each segment is mounted on an individual segment support assembly (SSA) and all the segments are brought to be aligned in the telescope structure to achieve monolithic profile of primary. The primary source of error which would lead to degradation in image quality (80% EE) would be from the primary mirror. Deviation of monolithic profile of the primary mirror would significantly degrade the image quality. Various error sources which could cause the deviation of the monolithic profile and which in turn affects the image quality have been identified. The effect of each of these error sources and its sensitivity to the image quality has been studied independently. Here we will discuss about the cause and significance of each of the error term originating from primary mirror as part of the error budget to the telescope.