The R2Pub, built by Beijing Planetarium, is a state-of-the-art 60 cm equatorial binocular telescope located at the Daocheng Site (with an altitude of 4700 m) of Yunnan Observatories in China. This paper provides an overview of the R2Pub telescope system, discusses its design and capabilities, and presents an evaluation of its performance for astronomical surveys. R2Pub is a prime-focus binocular system, with each tube covering a field of view of about 18 deg2. This system is designed to detect various transients in local universe, including variables, eclipsing binaries, supernovae, gamma-ray bursts afterglow, tidal disruption events, Active Galactic Nuclei, and other unknown transients, which are ideal targets for both time-domain astronomy research and science population. The entire R2Pub system has completed the construction and installation of all observatory infrastructure, including the dome, equatorial mount, optical tube, and associated components, and has now entered the commissioning phase. The high-altitude location, good seeing, and dark background sky light at Daocheng site ensure optimal observational conditions for time-domain astronomy. Performance testing during the commissioning phase has demonstrated that the R2Pub system can achieve a 5 sigma limiting magnitude of approximately 18.7 mag in the Pan-STARRS r ' band for 60 s exposures. The ongoing observations from R2Pub is expected to contribute significantly to the study of time-variable phenomena in the universe and greatly improve the public outreach in astronomy. In particular, the binocular telescope systems capable of simultaneous dual-band observations can obtain the instantaneous color information of transient sources, enabling more accurate characterization of their physical properties and evolution, and providing a significant advantage in rapid distinguishing different classes of variables and transients.

Robotic telescope networks play an important role in capturing early and bright optical afterglows, providing critical insights into the energetics and emission mechanisms of GRBs. In this study, we analyze GRB 230204B, an exceptionally energetic and multipulsed long GRB, detected by the Fermi Gamma-ray Burst Monitor and MAXI detectors, with an isotropic equivalent gamma-ray energy exceeding 10 ^54 erg. Time-resolved spectral analysis reveals a transition in the prompt emission from hard (sub-photospheric-dominated) spectra during early pulses to softer (synchrotron-radiation-dominated) spectra in later pulses, indicative of a hybrid jet composition. We report the discovery and characterization of the optical afterglow using the Mobile Astronomical System of Telescope-Robots (MASTER) and Burst Observer and Optical Transient Exploring System (BOOTES) robotic telescope networks, which enabled rapid follow-up observations starting at ∼1.3 ks post-burst. The optical luminosity at this time was exceptionally high, surpassing that of many other optically bright GRBs, such as GRB 990123 and GRB 080319B. This places the burst among the most luminous optical GRBs observed to date. Long-term radio observations extending to 335 days post-burst were conducted with the Australia Telescope Compact Array. Multiwavelength modeling, incorporating data from MASTER, BOOTES, Devasthal Optical Telescope, Swift/XRT, and radio observations, was conducted using an external interstellar medium (ISM) forward-shock top-hat jet model with afterglowpy . The results reveal a narrow and highly collimated jet with a circumburst density of n _0 ∼ 28.12 cm ^−3 , kinetic energy E _K ∼ 4.18 × 10 ^55 erg, and a relatively low value of ϵ _B = 2.14 × 10 ^−6 , indicating shock-compression of the magnetic field in the surrounding ISM. We constrained a low radiative efficiency of ∼4.3%. This study highlights the indispensable contribution of robotic networks to early afterglow observations and advances our understanding of GRB 230204B unique characteristics and underlying jet physics.

The Chinese Academy of Sciences (CAS) has already launched an ambitious project to build a large optical/infrared telescope leading by National Astronomical Observatories, CAS and joined by several other institutes of the CAS. The telescope will be located at the platform A of Lenghu site in Qinghai province, with an altitude of 4,350 meters. The effective aperture of the telescope is 14.5 meters with a segmented primary mirror composed of 120 hexagonal segments. The telescope is planned to be equipped with a suite of high performance scientific instruments as its first generation instruments. These includes an optical imaging spectrographs, a near infrared imager that will be assisted with sodium laser guide star adaptive optics system, and a near infrared high-resolution spectrographs. The performance of the telescope and the instruments will be limited by the local astronomical weather conditions. Parameters like wind speed/directions, relative humidity, temperature will have direct impact on the structures, materials, components of the telescope, its enclosure, and the scientific instruments. Cloudiness, atmospheric transparency, extinction, seeing, sky background, etc. will also affect the observation performances of the telescope and the instruments, which could also be used as a guide for operation of the telescope and instruments as well as be used in scientific data reductions. Especially considering that the telescope will have laser guide star adaptive optics system, the site monitoring plan should also include the monitoring of vertical turbulence profile, isoplanatic angle, coherent time, and if possible the monitoring of sodium layer altitude and density, which are all important for the performance of the laser guide star adaptive optics system. To ensure that the telescope and its instruments can achieve their optimal performances, it is essential to have a comprehensive site monitoring plan in place. This plan will involve the continuous monitoring of various atmospheric and environmental parameters at the telescope site. The data collected will be crucial for understanding the local astronomical conditions and for making informed decisions regarding to the operation and maintenance of the telescope and its instruments. In this paper, the initial site monitoring plan for the 14.5 meters optical / infrared telescope will be presented. The plan covers the parameters to be monitored, the reasons for monitoring them, and the instruments planned to be used.

Modern large telescopes rely on active optics for optimal image quality, but this technology is challenging to apply to thick mirror systems due to their high rigidity. The 2.4-m telescope at Lijiang Observatory has experienced significant image quality degradation, with the stellar full width at half maximum (FWHM) increasing from approximately 1 to over 2 arcseconds despite similar seeing conditions. This decline is attributed to high-order aberrations, including astigmatism, trefoil, and tetrafoil, which are uncorrectable by conventional focus adjustments. This study investigates, for the first time in China to our knowledge, the application of free-vibration-mode-based active correction—previously successful on thin-mirror telescopes—to a thick-mirror system. Using an 18-point active support system, we employed finite element modeling to evaluate the correction capabilities for various aberration modes. The simulations demonstrate high correction efficiency for astigmatism (>95%), along with significant correction for trefoil (84.47%) and tetrafoil (74.50%). However, the actuator forces required to correct trefoil, tetrafoil, and spherical aberration (31.33% efficiency) exceed practical limits. Therefore, the 18-point system is primarily effective for astigmatism correction. These results validate that free-vibration mode-based active optics offer a practical and effective solution for mitigating astigmatism in existing thick-mirror telescopes, thereby improving their observational performance.

We report a new standalone Robotic All-Sky narrowband Imager(RASI)for auroral and airglow studies.RASI has new optics and an electromechanical system,low operation and installation costs,easy deployment and fully automatic features.The new optics provide an all-sky field of view with excellent image quality and sensitivity.The new electromechanical system design offers a more compact size and the capability for outdoor independent deployment.We have also developed a fully automatic data acquisition software for RASI,which is based on the perception of solar altitude and the all-sky cloud cover.In conclusion,the RASI demonstrates significant advantages over the traditional all-sky narrowband imager,and it is highly suitable for the intensity measurements of large-scale auroras and airglow distributions.

ABSTRACT We present optimized physical parameters of the active eclipsing binary system USNO-B1.0 1387-0467554 discovered recently in Yunnan–Hong Kong wide-field photometric (YNHK) survey, based on the analysis of its two colour light curves and low resolution spectra obtained at Yunnan Observatories, China. Its spot distributions are derived by means of the Wilson–Devinney code, using photometric data of the YNHK survey from 2016 to 2021. There exist active longitude belts for the spot activities on the primary star, for which the effect of tidal force seems dominant comparing with the one of common magnetic field of the binary system. We have investigated its chromospheric activities through the indicators including Hα, Hβ, CaII H&K, and HeI D3 lines covered by the low resolution spectroscopic observations. There are obvious spatial correlations between the magnetic activities in its photosphere and chromosphere. The EHα/EHβ values suggest that both plages and prominences led to the emissions seen in the Balmer lines at most phases. A prominence structure appeared around the phase of 0.8 on 2018 October 25 and evolved in November and December, 2018. The spectra demonstrate that there were frequent flare events in the system. Moreover, the decay part of a white-light flare event was hunted by the YNHK survey on 2021 October 26.

远程天文台(Remote Observatory,RO)具有观测效率高、运行成本低等优点,因此远程观测应用越来越广泛.5G网络技术的发展为利用手机等移动终端实现远程观测提供了可能,物联网(Internet of Things,IOT)和社交网络(Social Networks,SN)技术的进步也为其提供了数据传输、数据共享以及人性化操作的新途径.为实现云南天文台14英寸望远镜的远程观测,验证基于物联网和社交网络的远程天文台技术,自行设计研发了一套远程天文台控制软件,以微信聊天模式收发控制命令,以微信图片格式传输观测图像,以微信群组方式控制用户权限,实现了手机等移动终端基于微信的远程观测功能,为远程天文台控制软件设计及社交网络在天文观测中的应用提供了可借鉴的经验和方法.

Polarimetry plays an important role in investigating physical properties for celestial objects. We present a polarimeter named YFPOL for the Cassegrain focus of the Lijiang 2.4 m Telescope (LJT) of Yunnan Observatories, Chinese Academy of Sciences. YFPOL is a traditional single-beam polarimeter with a rotating polarizer. As the focal-reducer instrument Yunnan Faint Object Spectrograph and Camera (YFOSC) is always positioned on the Cassegrain focal plane of LJT, we develop two sets of ultra-thin (thickness <12 mm) polarizer rotation control systems with wireless charging and control functions, which are suitable for mounting on the two front-wheels of YFOSC. One set is used as the polarimetric calibration unit, and the other is for the polarimetric modulation unit. Both of the polarizers have an ultra-high contrast ratio of 1,000,000:1 in the optical band. We investigate the instrumental polarization characteristics (IPCs) in the full field of view that is transferred from YFOSC. Furthermore, we identify that the IPCs change when the Cassegrain axis rotates. The spurious polarization from the IPCs can be effectively minimized by flat-fielding using the unpolarized domeflat, when the Cassegrain rotation angle is the same or nearest to that of the polarization observation. We develop a quasi-automatic pipeline for YFPOL and its effectiveness has been verified by tests of the polarimetric observation with blazar S5 0716+714. The calibration is performed by observing the zero-polarized and highly-polarized standard stars. We successfully reach high precision polarization in the 7 ′ field of view, and the systematic uncertainty is below 0.8% for a V = 11.68 target with a 10 s exposure. The instrument polarization angle offset is 2.°6. YFPOL is not only a simple polarimeter, but also a spectropolarimeter with grisms that can be considered in the future.

ABSTRACT We have discovered a young, rapidly rotating active star USNO-B1.0 1388−0463685 with a rotational period of 0.508750 ± 0.000153 d in the Yunnan–Hong Kong wide-field photometric survey. Based on the chromospheric activity identified in the dedicated spectroscopic observations, the brightness variation of this star is attributed to cool spots on its photosphere. We derived the spot maps from 14 light curves, which demonstrate that the strong spot tends to appear in the same hemisphere, and the light curve amplitude varies with a period of about 2.4 yr. Low-resolution spectroscopic observations revealed the chromospheric activity of the star through the indicators Hα, Na i D1 and D2, He i D3, and Ca ii H & K lines. Moreover, there was a clear anticorrelation between the equivalent width variation of the Hα, Na i D1 and D2 lines and the simultaneous light curve, implying the photosphere and chromosphere connection. Using the spectral subtraction technique, the spectral type of the star was determined as K0–2V and its projected rotational velocity v sin i is 107.492 ± 7.388 km s−1. Both the lithium equivalent width of 254.0 ± 43.3 mÅ and its location on the Hertzsprung–Russell diagram indicate that this star should be in the stage from late pre-main sequence to zero-age main sequence.

We are running a wide field photometric survey under the collaboration between Yunnan Observatories and Hong Kong Astronomical Society with a Centurion 18-inch telescope at the Lijiang station of Yunnan Observatories, China. Its scientific goals are discovering new transiting exoplanetary systems and other types of variable stars, and studying asteroids of the solar system. The survey was designed to monitor several fixed sky areas through time series photometry with short cadences. Since 2016, numerous observing data have been accumulated and reduced by means of dedicated pipelines to deliver the light curves for tens of thousands objects, which are cross-matched through the Carlsberg Meridian Catalog 15 or USNO-B1.0 catalog. Systematic errors and trends that existed in the raw photometric results are simulated through selected reference stars and then removed to improve signal-to-noise ratios of the light curves, which is crucial to detect weak signals like exoplanet transits and other variable stars of low amplitudes in brightness variations. The final data products own the photometric precision better than 0.01 magnitude for stars brighter than 13.8 magnitude in the V band. By means of generalized Lomb-Scargle, phase dispersion minimization, and box-fitting least squares techniques, we have already identified about a thousand of variable stars from the survey, including transiting exoplanet candidates, spotted stars, eclipsing binaries, pulsating stars, and so on. In addition, we have also captured around a thousand of asteroids of the solar system in the survey fields and produced their light curves due to spins.

Long-duration gamma-ray bursts (GRBs) associated with supernovae (SNe) are believed to originate from massive star core-collapse events, whereas short-duration GRBs that are related to compact star mergers are expected to be accompanied by kilonovae. GRB 211227A, which lasted about 84 s, had an initial short/hard spike followed by a series of soft gamma-ray extended emission at redshift z = 0.228. We performed follow-up observations of the optical emission using BOOTES, LCOGT, and the Lijiang 2.4 m telescope, but we detected no associated supernova signature, even down to very stringent limits at such a low redshift. We observed the host galaxy within a large error circle and roughly estimated the physical offset of GRB 211227A as 20.47 ± 14.47 kpc from the galaxy center. These properties are similar to those of GRB 060614, and suggest that the progenitor of GRB 211227A is not favored to be associated with the death of massive stars. Hence, we propose that GRB 211227A originates from a compact star merger. Calculating pseudo-kilonova emission for this case by adopting the typical parameters, we find that any associated pseudo-kilonova is too faint to be detected. If this is the case, it explains naturally the characteristics of the prompt emission, the lack of SN and kilonova emission, and the large physical offset from the galaxy center.

丽江2.4 m望远镜作为目前国内最大口径的通用型光学望远镜,在我国的夜天文观测领域有着十分重要的地位.从近几年观测时间分配的整体情况来看,云南暗弱天体成像光谱仪(Yunnan Faint Object Spectrograph and Camera,YFOSC)的光谱观测在2.4 m望远镜总观测时间中的占比最多,因此,提高其光谱观测效率和数据质量成为保证望远镜稳定科学产出的关键因素.从影响光谱观测效率的两个重要因素——星像入狭缝和望远镜闭环跟踪出发,介绍了提高2.4 m望远镜光谱观测效率和质量的方法.经实际测试,采用新算法的星像入狭缝精度提高了50％左右,时间缩短了7 min左右;望远镜1 h闭环跟踪精度优于0.5″,同时在像平面上的星像位置偏移量不大于1.8 pixel.

In recent years, the spectral data of celestial bodies observed have achieved a dramatic increase thanks to the successful implementation of various projects of spectral sky survey. Therefore, higher requirements for the automatic classification and analysis of spectrum are proposed for large-scale projects of spectral sky survey. The classification problem is transformed into a regression one in this paper, and a method of spectral category regression based on the residual depth network is put forward to conduct a prediction of MK spectral subtype on stellar spectrum. The network is mainly composed of 25 convolution layers, 1 maximum pooling layer, 1 average pooling layer, full connection layer and 12 residual structures. The maximum pooling layer is used to filter features, the convolution layer to extract features, and the average pooling layer to reduce parameters and improve efficiency. The residual structure can prevent the degradation of the network, extract high-dimensional abstract features by deepening the network and improve training speed. Considering the non-zero probability of data with false labels and corrupted data, Log-Cosh is adopted as a loss function in this paper to reduce the negative impact of bad samples. 80 000 spectra that are randomly selected from LAMOST DR5 are used as the experimental data. The spectra are divided into the training set, verification set and test set according to the proportion of 7 1 2 after eliminating the bad value and normalizing the flow. The experiment includes two parts. In the first part, the network is adopted to carry out a prediction on the spectral subtype, and the maximum absolute error, the average absolute error and the standard deviation are used to compare the performance of convolution kernels with different shapes. The predicted value is taken as the abscissa and the label as the ordinate, and the second-order nonlinear fitting is used for all sample points in the test set, a straight line that is coincident with y=x is obtained, proving that the model can predict the spectral subtype well. The second part is concerning the internal analysis of the model. The main characteristics of the model in predicting four types of spectra, A, F, G, K, are mainly explored with the method of category activation mapping, thus endowing the model with interpretability. In the text data set, 91. 4% of the spectral prediction errors of this method are within 0. 5 spectral subtypes, and the average absolute error of the prediction is 0. 3 spectral subtypes. It is shown that the method proposed in this paper can better predict spectral subtypes with faster speed and higher accuracy according to the comparison of the same data set with nonparametric regression, Adaboost regression tree and K-means.

随着天文技术的不断发展,远程观测和自主观测逐渐成为天文观测的主流趋势,自动调焦技术也越来越受到重视.电动调焦器是天文望远镜不可或缺的附属设备,是实现自动调焦的关键设备.为实现云南天文台丽江观测站10英寸米德望远镜的自动调焦,自行研发了一套天文电动调焦器,设计相关控制电路,制定串口通信协议,并编写了一套开源天文公共对象模型(Astronomy Common Object Model,ASCOM)驱动程序SS Focuser,详细介绍了该电动调焦器的结构原理和实现方法,实测结果表明,电动调焦器具有很好的稳定性,完全满足设计要求,为天文电动调焦器设计提供了可借鉴的经验和方法.

南极高原拥有独特的天文观测优势,为了对南极中山站夜天文观测条件进行实测研究,中国科学院云南天文台专门研制了一套具有耐低温、自动除雪除霜等适应南极气候特征的全自动全天信息采集系统,该系统可以提供实时的全天云量、天光背景和全天图像,并将信息推送到网页实时显示.介绍了系统的研制及为适应南极气候进行的耐低温实验,统计分析了中山站2016～2017年的全天信息数据,结果显示,中山站2016和2017年的可观测时间为772.21 h和437.38 h,可观测夜数为93 d和51 d,天光背景最大真实值为22.05 Mag/arcsec2,年平均气温为-10.6℃,最高气温19.1℃,最低气温为-44℃,2016年平均相对湿度为55.2％.

望远镜的观测日志在用户进行数据处理以及台站对观测数据进行存储、归档和发布时都非常重要,观测日志往往能提供很多信息以供用户判断观测数据的质量.在观测过程中,观测日志通过观测助手或用户手工记录,存在信息不全、笔误等多种可能,且纸质的观测日志也不利于后期数据的归档和发布.针对丽江2.4 m望远镜云南暗弱天体成像光谱仪的观测数据,设计研发了一套自动记录观测日志的辅助系统,该系统可以自动记录观测数据的日志信息,并提供修改错误信息的功能;系统中以用户的观测时间申请书编号为唯一代码对数据进行管理,从而实现了根据不同用户进行观测数据打包的功能.在保护观测数据权限的同时,降低了笔误带来的影响,提高了观测日志的准确性,最终提高望远镜的观测效率.

We installed two sets of Astronomical Site Monitoring Systems (ASMSs) at Lijiang Observatory (GMG), for the running of the 2.4-meter Lijiang optical telescope (LJT) and the 1.6-meter Multi-channel Photometric Survey Telescope (Mephisto). The Mephisto is under construction. The ASMS has been running on robotic mode since 2017. The core instruments: Cloud Sensor, All-Sky Camera and Autonomous-DIMM that are developed by our group, together with the commercial Meteorological Station and Sky Quality Meter, are combined into the astronomical optical site monitoring system. The new Cloud Sensor’s Cloud-Clear Relationship is presented for the first time, which is used to calculate the All-Sky cloud cover. We designed the Autonomous-DIMM located on a tower, with the same height as LJT. The seeing data have been observed for a full year. ASMS’s data for the year 2019 are also analysed in detail, which are valuable to observers.

The Lijiang 2.4-m telescope was built and opened to astronomers since 2008, now there are several instruments installed at the telescope. The control system of the 2.4-m telescope was designed to be operated in robotic mode as the Liverpool telescope, but due to many reasons it didn’t achieve robotic mode until now. After we upgraded the fold mirror by adding a rapid instrument exchanging system at the Cassegrain focus in 2012, now we can have up to 9 instruments on the telescope at the same time, but the control system for the instrument is still specific for each instrument. During the observation, change to different control software and operating system for different instrument are needed, which affects the observation significantly. Following the observation control system for few years, we are trying to develop a suitable observation control system for the Lijiang 2.4-m telescope. In this paper, we will introduce the Lijiang observatory, the 2.4-m telescope and its instruments at first, and then discuss the concept design of observation control system for this telescope which will based on the main purpose of improving the observation efficiency.