An effort towards understanding the problems associated with stray light related to the Xinglong2.16-m telescope is presented to estimate the stray light performance of the telescope itself and provide a method for im...An effort towards understanding the problems associated with stray light related to the Xinglong2.16-m telescope is presented to estimate the stray light performance of the telescope itself and provide a method for improving stray light suppression.Stray light analysis for the 2.16-m telescope model,which consists of an onion shaped dome,telescope structure,equatorial mount and telescope optics,has been developed in two cases(1)pointing to 60?and(2)pointing to zenith,in both azimuth and elevation directions.The Point Source Normalized Irradiance Transmittance(PSNIT),which is generally used for assessing stray light and is uncorrelated to entrance aperture,is calculated with a series of off-axis angles.It shows that the PSNIT values are less than 10-7 when off-axis angles are larger than±20?.The dominant contributors to stray light(primary and secondary mirror,telescope structure and dome)are identified to guide performance improvement.The analyses indicate that significant benefit can be realized by adding only five vanes inside the bottom portion of the secondary baffle.In the case of pointing to zenith,the PSNIT values will decrease about 40%on average.展开更多
The 85-cm telescope at Xinglong station is a prime focus system that operates well with high science outputs. The telescope has been upgraded since 2014 with a new corrector, and new filters and camera, which are prov...The 85-cm telescope at Xinglong station is a prime focus system that operates well with high science outputs. The telescope has been upgraded since 2014 with a new corrector, and new filters and camera, which are provided by Beijing Normal University. The filter set is the Johnson-Cousins UBV RI system. We report the test results of the new system including bias, dark current, linearity, gain and readout noise of the CCD camera. Then we derive accurate instrumental calibration coefficients in UBV RI bands with Landolt standard stars during photometric nights. Finally, we give the limiting magnitudes with various exposure times and signal-to-noise ratios for observers as references.展开更多
The telescopes and the infrastructures may alter the local wind environment around the observatory and further affect the observing environment.After the completion of site testing,it is necessary to analyze the wind ...The telescopes and the infrastructures may alter the local wind environment around the observatory and further affect the observing environment.After the completion of site testing,it is necessary to analyze the wind environment of the entire site and plan the telescope layout to make use of the excellent conditions scientifically and rationally.Taking a typical observatory as an example,the effect of topographical features on the wind environment and the mutual interference between telescope enclosures are analyzed by using the Computational Fluid Dynamics(CFD)method.The CFD simulations are compared with the seeing data from the Differential Image Motion Monitor,and the results are in good agreement,which verifies the effectiveness of the CFD method.The results of wind environment analysis can provide reasonable suggestions for site layout and construction,reducing the interference effects and improving the observing environment.展开更多
The Large Optical/infrared Telescope(LOT)is a ground-based 12 m diameter optical/infrared telescope,which is proposed to be built in the western part of China in the next decade.To select the best site which satisfies...The Large Optical/infrared Telescope(LOT)is a ground-based 12 m diameter optical/infrared telescope,which is proposed to be built in the western part of China in the next decade.To select the best site which satisfies the construction and future operation of LOT,data monitoring and comparing are required for all the candidate sites.The comparison of most of the instruments was done at Xinglong Observatory.These instruments include weather station,all sky camera,sky background meter and differential image motion monitor(DIMM).This paper introduces the instruments used in LOT site monitoring and the instruments comparisons.The results show that the instrument is stable and the data uniformity of the identical instruments is good.This paper provides a fundamental description of LOT site monitoring.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11703043)Joint Research Fund in Astronomy,National Natural Science Foundation of China(No.U1831209).
文摘An effort towards understanding the problems associated with stray light related to the Xinglong2.16-m telescope is presented to estimate the stray light performance of the telescope itself and provide a method for improving stray light suppression.Stray light analysis for the 2.16-m telescope model,which consists of an onion shaped dome,telescope structure,equatorial mount and telescope optics,has been developed in two cases(1)pointing to 60?and(2)pointing to zenith,in both azimuth and elevation directions.The Point Source Normalized Irradiance Transmittance(PSNIT),which is generally used for assessing stray light and is uncorrelated to entrance aperture,is calculated with a series of off-axis angles.It shows that the PSNIT values are less than 10-7 when off-axis angles are larger than±20?.The dominant contributors to stray light(primary and secondary mirror,telescope structure and dome)are identified to guide performance improvement.The analyses indicate that significant benefit can be realized by adding only five vanes inside the bottom portion of the secondary baffle.In the case of pointing to zenith,the PSNIT values will decrease about 40%on average.
基金support from the staff at the Xinglong 85-cm telescopesupport from the National Natural Science Foundation of China(NSFC)through grant 11673003+3 种基金the National Basic Research Program of China(973 program,2014CB845700)partially supported by the Open Project Program of the Key Laboratory of Optical Astronomy(National Astronomical Observatories)NSFC under Grant Nos.11403088 and 11273051(Xinjiang Astronomical Observatory)Chinese Academy of Sciences and Department of Astronomy,Beijing Normal University
文摘The 85-cm telescope at Xinglong station is a prime focus system that operates well with high science outputs. The telescope has been upgraded since 2014 with a new corrector, and new filters and camera, which are provided by Beijing Normal University. The filter set is the Johnson-Cousins UBV RI system. We report the test results of the new system including bias, dark current, linearity, gain and readout noise of the CCD camera. Then we derive accurate instrumental calibration coefficients in UBV RI bands with Landolt standard stars during photometric nights. Finally, we give the limiting magnitudes with various exposure times and signal-to-noise ratios for observers as references.
基金supported by the National Natural Science Foundation of China(U1831209)。
文摘The telescopes and the infrastructures may alter the local wind environment around the observatory and further affect the observing environment.After the completion of site testing,it is necessary to analyze the wind environment of the entire site and plan the telescope layout to make use of the excellent conditions scientifically and rationally.Taking a typical observatory as an example,the effect of topographical features on the wind environment and the mutual interference between telescope enclosures are analyzed by using the Computational Fluid Dynamics(CFD)method.The CFD simulations are compared with the seeing data from the Differential Image Motion Monitor,and the results are in good agreement,which verifies the effectiveness of the CFD method.The results of wind environment analysis can provide reasonable suggestions for site layout and construction,reducing the interference effects and improving the observing environment.
基金partly supported bythe Operation Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted from the Ministry of Finance of China(MOF)and administrated by the Chinese Academy of Sciences(CAS)the grants from Joint Research Fund in Astronomy from the National Natural Science Foundation of China(Nos.U1831209 and U1731131)Youth Innovation Promotion Association CAS(No.2017077)。
文摘The Large Optical/infrared Telescope(LOT)is a ground-based 12 m diameter optical/infrared telescope,which is proposed to be built in the western part of China in the next decade.To select the best site which satisfies the construction and future operation of LOT,data monitoring and comparing are required for all the candidate sites.The comparison of most of the instruments was done at Xinglong Observatory.These instruments include weather station,all sky camera,sky background meter and differential image motion monitor(DIMM).This paper introduces the instruments used in LOT site monitoring and the instruments comparisons.The results show that the instrument is stable and the data uniformity of the identical instruments is good.This paper provides a fundamental description of LOT site monitoring.
