Study On Measurement Technology Of Atmospheric Transmittance In Whole Layer At Night

Stars at night after entering the earth's atmosphere,radiated by the atmosphere molecules,the role of absorption and scattering,aerosol particles reach the ground radiation attenuation.Stellar radiation effect of the whole layer of the atmosphere through the whole atmospheric transmittance,it reflects the extinction properties of the whole layer of the atmosphere.Atmospheric transmittance measurement of the whole layer can fix atmospheric change caused by light transmission.Based on the original day and night the whole layer atmospheric transmittance instrument,this thesis improves the measurement method of the whole night layer atmospheric transmittance.The new method of using automatic control CCD exposure time for star sub-band radiation signals,replaces the original enhanced CCD(ICCD),simplifies the instrument calibration,and improves the measurement precision and sensitivity.The night of the whole layer atmospheric transmittance instrument consisting of telescope and tracking system,filter mechanism and CCD acquisition system,using the technology of image recognition,feedback to solve the telescope automatic tracking stars lose target problem for a long time.According to the collected image signal strength value automatically adjust the CCD exposure time to achieve automatic continuous observation.Instrument capturing target uses the Langley-plot method combined with multi-objective star calibration method,which simplifies instrument calibration.In Hefei area using the newly developed at night the whole layer atmospheric transmittance instrument measures the whole night atmospheric transmittance,and obtains the whole sub-band layer of the atmosphere transmittance at night.Measurement results compared with the MODTRAN and CART simulation results,prove the feasibility of measuring methods and equipment reliability.