NIAOT OpenIR

The Mini-SiTian Array:Optical Design

Wed, 29 Apr 2026 08:29:34 GMT

Title: The Mini-SiTian Array:Optical Design Authors: Han ZJ(韩子健); Li ZY(李正阳); Chen C(陈超); Cong JN(丛迦南); Liu TT(刘婷婷); Zhang YM(张一鸣); Kong WB(孔维斌) Description:

Time-domain astronomy is one of the most important areas.Large sky area,deep-ﬁeld,and short timescale are the priority of time-domain observations.SiTian is an ambitious ground-based project processing all sky optical monitoring,aiming for a sky-survey timescale of less than 1 day.It is developed by the Chinese Academy of Sciences,an integrated network of dozens of 1 m class telescopes deployed worldwide.The Mini-SiTian Telescope Array is being carried out for demonstrations on optical design,group scheduling,and software pipeline developments,to overcome the high technical andﬁnancial difﬁculties of the SiTian project.One array contains three 300 mm F/3 telescopes,with an FOV of 5°over the 400–1000 nm wavelength range.The Mini-SiTian Telescope Array is now under commissioning in Xinglong Observatory,and a perfect platform for technical research and educational purposes.

Study on wide-field Ground Layer Adaptive ptics system for Chinese Large Optical/Infrared Telescope

Wed, 29 Apr 2026 08:19:46 GMT

Title: Study on wide-field Ground Layer Adaptive ptics system for Chinese Large Optical/Infrared Telescope Authors: Pei C(裴冲); Yuan XY(袁祥岩); Zuo H(左恒); Fu Y(傅莹); Cui XQ(崔向群) Description:

The 12-m optical infrared telescope is a proposed large-scale general-purpose tele scope in China.This telescope will integrate Ground Layer Adaptive Optics(GLAO) to effectively mitigate the effects of atmosphere turbulence within a 14′field of view, thereby enhancing observational efficiency and scientific performance.To system atically assess the correction capabilities of the 12-m telescope with GLAO under various error conditions,simulations were conducted using the Durham Adaptive Optics Simulation Program.The correction performance is highly dependent on the atmospheric turbulence model,guide star,and wavefront sensor system configura tions.Under typical site conditions with seeing of 0.8″,the GLAO system can correct ∼70%turbulence in the ground layer,resulting in a full width at half maximum (FWHM)of 0.35″at 840 nm and 0.27″at 1200 nm,corresponding to correction gains of 1.6×and 1.9×,respectively.The system also achieves a 1.3×improvement in half-light radius(θ5 0)and 2.0×enhancement in encircled energy within 200 milliarc seconds(EE2 00 mas).Additional system aberrations,including system pupil shape, phasing,alignment,and noncommon path aberrations,introduce measurable per formance degradation:increasing FWHM by 10.0%(840 nm)and 3.0%(1200 nm), θ5 0by 15.0%and 8.7%,and reducing EE 200 masby 24.0%and 9.4%,respectively.
We also investigate the impact of large-aperture adaptive deformable mirrors,simu lated by finite element software,on the performance of GLAO system.Key factors such as influence function,conjugate height,tilt angle and off-zenith observation are considered.

Spectral Eﬃciency Testing and Error Analysis of Space Slitless Spectrograph

Wed, 29 Apr 2026 08:11:52 GMT

Title: Spectral Eﬃciency Testing and Error Analysis of Space Slitless Spectrograph Authors: Li S(李顺); Ji HX(季杭馨); Zhang HT(章华涛); Zhang SL(张淑玲); Hu ZW(胡中文) Description:

The slitless spectroscopy assembly of the China Space Survey Tele scope(CSST)will be installed in front of the main focal plane detector of the sky survey module to conduct wide-ﬁeld,wide-band slitless spectral observations. As an important dispersion element of the sky survey module,the slitless spec troscopy assembly is composed of 24 gratings and 12ﬁlters.Spectral eﬃciency is one of the key technical parameters of the slitless spectroscopy assembly,and it needs to be tested during the development process.Due to the large envelope of the slitless spectroscopy assembly,commercial spectral eﬃciency measurement equipment cannot be used for testing.This paper addresses the issue of spectral eﬃciency testing for the slitless spectroscopy assembly.Firstly,the basic struc ture and measurement principles of the slitless spectroscopy assembly spectral eﬃciency test platform built in the laboratory are introduced.Then,the steps and results of the spectral eﬃciency measurement for the qualiﬁcation model of the slitless spectroscopy assembly are given.Finally,the accuracy of the mea surement results is analyzed and calculated using error synthesis theory.The measurement and calculation results show that the average spectral eﬃciency of the qualiﬁcation model for the slitless spectroscopy assembly is respectively 51.9%in the GU band,67.9%in the GV band,and 71.6%in the GI band(67.7% in the 900 nm–1000 nm band),meeting the technical requirements.

Research on PMAC System for the“WeHoST”2.5-meter telescope based on ADRC

Wed, 29 Apr 2026 08:01:53 GMT

Title: Research on PMAC System for the“WeHoST”2.5-meter telescope based on ADRC Authors: 闫振帅; 叶宇; 赵特; 乐中宇; 顾伯忠; 韩硕 Description:

This paper presents an in-depth study of the application of Active Disturbance Rejection Control(ADRC)in the high-precision motion control system of the“WeHoST”2.5-meter large aperture telescope using a Programmable Multi-Axis Controller(PMAC).The goal is to enhance the telescope’s tracking accuracy and stability under complex environmental conditions.In response to disturbances encountered during the telescope’s observation process,an optimized solution based on ADRC was designed and implemented.At first,based on ADRC theory,a controller architecture was constructed,incorporating an Extended State Observer(ESO)and a Nonlinear State Error Feedback(NLSEF)control law.Subsequently,the key parameters of the controller were determined according to the specific parameters and performance requirements of the“WeHoST”telescope to ensure the controller’s fast response and stability.The ADRC was then implemented in the PMAC control system,and the telescope’s position was monitored in real-time using high-precision encoders. Experimental data show that the positioning accuracy of the“WeHoST”telescope was significantly improved after the introduction of ADRC.In dynamic tracking tests,the tracking error decreased from 0.01817′ ′ to 0.01261′ ′ ,a reduction of approximately 30.59%.The PP(Peak to Peak)value decreased from 0.04585′ ′ to 0.03201′ ′ ,a reduction of approximately 30.18%,significantly enhancing the telescope’s tracking accuracy and stability.The study successfully applied ADRC to the main axes of the“WeHoST”telescope.demonstrating its effectiveness in improving the tracking accuracy and stability of the telescope.It provides valuable insights and references for instruments requiring high-precision motion control.

Reliability Improvement Strategies for Telescope Control Systems

Wed, 29 Apr 2026 07:46:26 GMT

Title: Reliability Improvement Strategies for Telescope Control Systems Authors: Li Y(李运); Yang SH(杨世海); Deng ZZ(邓壮壮); Pan C(潘聪); Gu BZ(顾伯忠) Description:

The telescope drive control system provides essential power support for the successful execution of astronomical observations,and its reliability directly impacts the efﬁciency of these observations.This paper focuses on strategies for enhancing the reliability of the telescope drive control system,proposing a comprehensive and multidimensional reliability improvement solution.The study examines mechanisms for enhancing reliability from three perspectives:expected fault diagnosis,unanticipated state identiﬁcation,and reliability optimization during the design phase.For each of these aspects,speciﬁc reliability enhancement solutions are proposed,including a fault diagnosis and self-healing expert system,a generic process model for unanticipated state identiﬁcation,and an optimized tracking control strategy under timestamp synchronization.Furthermore,the paper demonstrates the feasibility of these solutions from the three aforementioned perspectives,providing a clear direction for the development of reliability enhancement strategies for telescopes.

Portable broadband astronomical spectrograph

Wed, 29 Apr 2026 07:32:18 GMT

Title: Portable broadband astronomical spectrograph Authors: Huang XL(黄小林); Wu JJ(吴佳佳); Liang Y(梁源); Wang J(王靓); Chen CD(陈传东); Li ZY(李正阳); Zhang K(张凯) Description:

Astronomical spectroscopy is a critical tool in many advanced research topics such as cosmic origin, galaxy evolution, stellar formation, and exoplanet detection. Medium-to-large aperture optical telescopes equipped with various spectrographs are suitable for many large programs. However, many small-aperture (30–80 cm) telescopes have the potential to perform quick and flexible observations in the astronomical field. Using current technology, most portable astronomical spectrographs can capture broadband spectra by rotating or changing the gratings to scan the spectrum at multiple exposures. This paper presents a portable broadband astronomical spectrograph (called ESPEC-2) that features an echelle grating as the main disperser and a group of collimating and imaging lenses to simplify the optical system. For 30–80 cm aperture telescopes, the lightweight prototype (~3.5 kg) enables spectral observation with a spectral resolution of R ≥ 6 200 over a wavelength range of 400–900 nm with a single exposure. Moreover, it can be directly mounted on the telescope’s focus or connected via optical fiber. Its portability and versatility make it suitable for use as a general-purpose spectrograph in other scientific experiments. The developed compact broadband spectrograph is expected to make significant contributions to scientific research, outreach, and education.

Photoacoustic tweezers generated by multiple superposed laser pulses in air

Wed, 29 Apr 2026 07:16:52 GMT

Title: Photoacoustic tweezers generated by multiple superposed laser pulses in air Authors: Tong GD(佟国栋); Xu LY(许立言); He JP(何晋平) Description:

We propose a novel method for generating photoacoustic tweezers via multi-ultrasonic resonance in air.In this study, a focused ultrashort laser pulse with a 50 ns pulse width is used to generate ultrasonic resonance by transferring thermal energy to atmospheric H2O in air.Traveling photoacoustic tweezers are generated by modulating the superposition of multiple ultrasonic waves.Through numerical simulations,we obtained the acoustic pressure and temperature fields of the photoacoustic waves.Experimentally,10µm microspherical polystyrene particles were placed messily in a 200µm wide square microfluidic tube.The resulting shapes of the microparticles after manipulation by the photoacoustic tweezers proved that our experimental results align well with theoretical predictions.We demonstrate that the interaction of laser pulses with water vapor can generate both acoustic waves and photoacoustic tweezers.

Performance Calibration of the Wavefront Sensor’s EMCCD Detector for the Cool Planets Imaging Coronagraph Aboard CSST

Tue, 28 Apr 2026 08:45:42 GMT

Title: Performance Calibration of the Wavefront Sensor’s EMCCD Detector for the Cool Planets Imaging Coronagraph Aboard CSST Authors: 窦江培; 牛炳力; 赵刚; 张熙; 王钢; 袁保宁; 王地; 钱星光 Description:

The wavefront sensor(WFS),equipped with an electron-multiplying charge coupled device(EMCCD)detector,is a critical component of the Cool Planets Imaging Coronagraph(CPI-C)on the Chinese Space Station Survey Telescope(CSST).Precise cali bration of the WFS’s EMCCD detector is essential to meet the stringent requirements for high-contrast exoplanet imaging.This study comprehensively characterizes key perfor mance parameters of the detector to ensure its suitability for astronomical observations. Through a multi-stage screening protocol,we identified an EMCCD chip exhibiting high resolution and low noise.The electron-multiplying gain(EM Gain)of the EMCCD was analyzed to determine its impact on signal amplification and noise characteristics,identi fying the optimal operational range.Additionally,noise properties such as readout noise were investigated.Experimental results demonstrate that the optimized detector meets CPI-C’s initial application requirements,achieving high resolution and low noise.This study provides theoretical and experimental foundations for the use of EMCCD-based WFS in adaptive optics and astronomical observations,ensuring their reliability for advanced space-based imaging applications.

Performance analysis and strategy optimization of mechanical defrosting for an Antarctic near-infrared telescope using aper ture photometry

Tue, 28 Apr 2026 08:35:26 GMT

Title: Performance analysis and strategy optimization of mechanical defrosting for an Antarctic near-infrared telescope using aper ture photometry Authors: Chen JL(陈家砺); Li ZY(李正阳); Cong JN(丛迦南); Zheng KW(郑凯文) Description:

Dome A, in Antarctica, offers an exceptional site for ground-based infrared astronomy, with its extremely low atmospheric infrared background noise and excellent seeing conditions. However, deploying near-infrared telescopes in the harsh environment of Antarctica faces the critical challenge of frost accumulation on optical mirrors. While indium tin oxide heating films effectively defrost visible-band Antarctic astronomical telescopes, their thermal radiation at infrared wavelengths introduces significant stray light, severely degrading the signal-to-noise ratio for infrared observations. To address this limitation, we have designed a mechanical snow-removal system capable of efficiently clearing frost from sealing window surfaces at temperatures as low as –80°C. Aperture photometry of target sources, Canopus and HD 2151, revealed that after six days without intervention, floating snow extinction reduced target brightness by up to 3 magnitudes. Following mechanical defrosting, the source flux recovered to stable levels, with measured magnitudes showing rapid initial improvement followed by stabilization. Data analysis indicates that a frost removal strategy operating every 48 h, with each operation consisting of 4–6 cycles, enables efficient removal of frost and snow without introducing additional thermal noise. Future work will focus on optimizing the adaptive control algorithm and exploring novel low-temperature defrosting materials to extend the periods during which Antarctic infrared telescopes can operate unattended.

Optimization Design and Analysis for the Mechanical Test Platform of Scientific Probe Module of the Cool Planet Imaging Coronagraph

Tue, 28 Apr 2026 08:28:59 GMT

Title: Optimization Design and Analysis for the Mechanical Test Platform of Scientific Probe Module of the Cool Planet Imaging Coronagraph Authors: Kong LY(孔令一); Dou JP(窦江培); Guo W(郭伟); Xu MM(许明明); Jiang S(江舒); Chen B(陈博) Description:

Tis paper optimizes the design and analysis of the mechanical test platform for the scientifc probe module of the Cool Planet Imaging Coronagraph,which is the ffth part of the China Space Station survey Telescope.First,according to the module layout and economic requirements,the preliminary structural design of the module mechanical test platform is carried out, and the stifness sensitive parameters of the assembly are identifed to determine the optimization parameters.Te central composite design method is used to design the test platform,and a third-order regression model is constructed for response surface analysis.Te third-order response surface model of the fundamental frequency and amplitude of the test platform is obtained by ftting the test data with the least squares method,and the structure of the module mechanical test platform is determined.Te modal analysis is carried out to determine the fundamental frequency and vibration modes of the mechanical test platform.Te vibration response of the platform is simulated by sine,random,and swept frequency vibration simulations. Te response surface ftting algorithm is verifed by the test platform swept frequency test.Te agreement between the response surface ftting algorithm and the experiment is good.Te fundamental frequency of the test platform is 436.2 Hz (>300 Hz),which meets the design index requirements of the test platform and can accurately guide the optimization design work.At the same time,it provides the theoretical basis and design method for the structural design of the Chinese manned space station.