Abstract Details
| Name: Narasimha Jayanth Affiliation: Manipal Institute Of Technology, Manipal Conference ID: ASI2019_499 Title : Development of a Customized Shack-Hartman Wavefront Sensor for the relative Radius of Curvature Measurement. Authors and Co-Authors : Narasimha Jayanth(1), Annu Jacob(2), Padmakar Parihar(2), Sriram S(2) Manoj Kumar(2) 1. Manipal Institute of Technology, Manipal. 2. Indian Institute of Astrophysics, Bangalore. Abstract Type : Poster Abstract Category : Instrumentation and Techniques Abstract : Shack Hartmann Wavefront Sensor (SHWS) device is most commonly used in Adaptive Optics Systems. However, the same device can also be effectively used as an optical metrology instrument to characterize any optical system made of lenses or mirrors. To get acquainted with SMT, a prototype segment mirror telescope (PSMT) is being designed and developed at Indian Institute of Astrophysics (IIA) Bangalore. The proposed prototype telescope will use seven hexagonal mirrors, which will be supported by simple mirror support assembly and driven by indigenously developed voice coil based actuators. The PSMT mirror segments are planned to be manufactured in IIA’ optics fabrication facility. One of the stringent requirement associated with the PSMT mirror segments is that they should have almost matching ROC and any relative departure in the ROC by few hundred micron will results in substantial degradation in the telescope image quality. During the optics manufacturing process, the relative ROC of mirror segments need be measured precisely and then after any departure from required ROC has to be corrected at the manufacturing stage itself. After exploring various options to measure ROC, the PSMT engineering team has come up with an approach which uses SHWS. Since SHWS needed for the optics metrology has got specific requirements and therefore any commercially available SH may not serve the purpose. Therefore, we attempted to develop a customized SHWS which can be used to test PSMT mirror segments. As a first step we design the optics of the instrument using ZEMAX, then after mechanical structure and the control. We also developed necessary software to control the instrument as well as data analysis software. At present, instrument is going through extensive calibration and testing in the laboratory. In this poster, we present the opto-mechanical design of the instrument, control and the preliminary test results. |