The Development Of NVST Integrated Control Terminal

One Meter Solar Telescope(or named New Vacuum Solar Telescope,NVST for short)is an alt-az vacuum solar telescope,its terminal equipments include five highresolution imaging channels,multi-wavelength solar spectrograph,large dispersion spectrograph and high-resolution two dimensions magnetograph.high-resolution imaging system has been used for routine observation,while others are still in development.NVST is a comprehensive solar observation instrument,which is developing more advanced solar observation technology,and carring out busy observation mission,so,it is of importance for NVST to improve performance and work effiently.However,the performance and effiency of NVST are influenced by many factors,because of it's complexity.And they still need to be perfected although NVST has beening working for several years.This paper aims to develop a control terminal in reserved imaging channel,which to implement automic defocus-detecting,correct the long-time tracking error and decrease image jitter causing by wind.All those problems have feasible resolutions,but there still are many technical obstacles to make those method practical.The purpose of NVST integrated control terminal is to eliminate these technical barriers and integrate these three subsystems.Using high speed camera and an electric moving stag with high precision that moves around the focus position can detect real-time focus position of NVST based on statistical ratio of power spectrum.And the required image can be used to calculate the shift with correlation algorithm,then integrated control terminal separate the low frequence error from the high frequence error.The low frequence error will be sent to the telescope system to improve the close-loop tracking accuracy,while the high one will be used to control the tip-tilt mirror for the purpose of reducing the image jitter causing by wind.The first chapter introduces the background and meaning of the study and the survey of relevant papers are given,and the key points of the study are also suggested.The second chapter proposes the overall structure of integrated control system and major parameters combined the test data.The third chapter introduces the implement of hardware and software,including optical structure,hardware system and software design.In fourth chapter,experiments results carried out using intergrated control system is displayed to verify the reliability of this system.The last chapter summarizes the development results and shortcoming of NVST intergrated control terminal.The test results show that three subsystems run stable and can coordinate with each other.The defocus-detect system has been using in routine observation since August 2016,and long-time tracking system performs reliable in experiment.As for image stablibity control based on tip-tilt,it's practicability has been proved in experiment,but it just provide a feasible project now.The optical structure of NVST must be considered if tip-tilt mirror is used as a routine observation tool.