1m红外太阳望远镜光电导行系统中像场旋转的分析

云南天文台1m红外太阳望远镜(YNST)光电导行系统是基于检测太阳像在面阵CMOS图像传感器上的偏移量作为反馈控制信号的高精度闭环跟踪系统[1]。由于YNST是一个地平式装置,在太阳像偏移检测量中存在着像场旋转量,为了获取稳定清晰的太阳像,必须对检测量进行消旋[2]才能达到光电导行系统的跟踪要求。根据球面天文学及天体测量学的知识并结合导行镜的光学系统,推导了光电导行系统中像场旋转的变化规律并对其进行模拟分析。     

1．2m地平式望远镜视场旋转研究与消旋

简要地讨论了1.2m地平式望远镜的运动特征,定量地给出物方视场旋转的公式,并对像方视场旋转的量和方向给予确定.通过对三种消旋方式的比较得出物理消旋更适合1.2m地平式望远镜视场消旋的结论.     

云台红外太阳望远镜中光电导行系统的像场旋转

红外太阳望远镜中的光电导行系统是高精度的反馈跟踪系统。在开环控制下,难以实现太阳望远镜的跟踪指标,所以必须使用光电导行作为目标位置反馈系统。但是在地平式系统跟踪过程中,光电导行望远镜中的像场会旋转,如果不进行消旋,光电导行系统就不能工作,这就需要解决光电导行系统中的像场旋转。本文在理论上分析了红外望远镜中光电导行系统的像场旋转,并给出了像在CCD面上的运动变化公式。     

云台红外太阳望远镜中光电导行系统的像场旋转

红外太阳望远镜中的光电导行系统是高精度的反馈跟踪系统。在开环控制下，难以实现太阳望远镜的跟踪指标，所以必须使用光电导行作为目标位置反馈系统。但是在地平式系统跟踪过程中，光电导行望远镜中的像场会旋转，如果不进行消旋，光电导行系统就不能工作，这就需要解决光电导行系统中的像场旋转。本文在理论上分析了红外望远镜中光电导行系统的像场旋转，并给出了像在CCD面上的运动变化公式。     

1 m红外太阳望远镜狭缝扫描控制系统的分析

1m红外太阳望远镜是地平式望远镜,其工作视场是3'×3'.为了得到像斑的二维光谱,需要做狭缝扫描.本文介绍了狭缝扫描控制系统的整体结构,根据望远镜的光路系统进行数学分析,说明了狭缝扫描控制系统的可行性,并指出了一些参数对系统的影响.     

1.2m地平式望远镜视场旋转角的理论计算

利用光线追迹法和矩阵光学的方法分析了1.2m天文望远镜折轴平面反射镜系统在望远镜的方位轴、高度轴转动时所引起的像方视场的旋转,分别用两种方法给出了一致的目标图像旋转与望远镜高度角、方位角之间变化的函数关系式,并将地平式装置引起的物方视场旋转在球面坐标系下的旋转量转换到平面直角坐标系中,最终得到整个望远镜系统的视场旋转量,为实时改正这些旋转量提供了理论依据.     

斜轴式天文望远镜运动特性研究

相对于传统地平式或赤道式望远镜,斜轴式天文望远镜因其独特的机架结构形式更加适应例如南极等的极端台址环境.但由于这种望远镜形式的应用较少,针对其运动特性的研究还比较缺乏.首先详细讨论了斜轴式望远镜的优缺点,推导了斜轴坐标系与地平和赤道坐标系之间的坐标变换关系,在此基础上研究了斜轴式望远镜在进行恒星跟踪时的运动特性,并与地平式望远镜进行了比较.另外,还研究了斜轴式望远镜的像场旋转特性,并分析了像旋对望远镜天线全息测量的影响.最后,还针对斜轴式望远镜的特点,推导了一套包含7个误差项的指向误差改正模型.     

1.2米地平式望远镜视场的旋转

本文定量地给出地平式装置所引起物方视场旋转的公式,并对1.2米地平式望远镜的平面反射镜系统随方位和高度的运动所引起的象方视场旋转角度的量和方向给予确定。     

1m红外太阳望远镜光电导行系统的反馈控制分析

我国正在研制中的1m红外太阳望远镜是目前国内唯一的地平式真空太阳塔,主要用于活动区磁场的精细光谱分析和太阳活动区磁场的时空精细结构研究.要求望远镜必须长时间高精度跟踪太阳(0.3"/30s、1"/10min)才能实现它的科学目标.光电导行是实现望远镜高精度跟踪观测目标的关键控制技术,通过检测观测目标像在图像传感器上的移动量作为反馈控制信号对望远镜实行闭环控制.首先建立了光电导行系统的控制系统模型,然后分析了系统的稳定性能、暂态性能、时域特性、频域特性及跟踪性能,并采用PID控制器对系统进行优化设计,以提高光电导行反馈控制系统的稳定性和跟踪精度.通过计算机仿真设计,采用PID控制算法能实现1m红外太阳望远镜的跟踪要求.     

AIMS太阳望远镜中像旋对稳像精度的影响分析

针对用于太阳磁场精确测量的中红外观测系统(Accurate Infrared Magnetic field measurements of the Sun, AIMS)太阳望远镜地平式机架在跟踪目标时像场旋转的现象,研究了像场旋转对稳像系统校正精度的影响。首先理论分析了互相关因子算法和绝对差分算法在不同湍流强度及不同探测窗口大小时由像场旋转引起的计算误差。随后在光学分析软件ASAP(Advanced Systems Analysis Program)中建立了包含装配误差的望远镜系统动态光学模型,统计了折轴系统装配误差在望远镜实时跟踪太阳运动时引起的像场平移及旋转。其中,图像在半小时内的最大平移约为0.3 mm,最大像旋约为200″。结果表明,在现有的误差分配情况下,装配误差引起的像旋对稳像精度的影响很小,而为了获得较高的稳像精度,互相关因子算法是首选的稳像算法,且在硬件处理速度允许的情况下,应该选择128×128像素的探测窗口。     

Adjustment of a tower solar telescope and spectrograph: A method manual

Questions of the mounting and adjustment of a tower solar telescope are considered through the example of the TST-2 telescope of the Crimean Astrophysical Observatory Scientific Research Institute. The authors describe the optical circuits of the telescope and spectrograph and list the basic requirements for the mutual arrangement of individual components of the telescope. Simple methods for adjusting elements of the telescope and spectrograph are described.     

Design and implementation of an image stabilization device at the THEMIS solar telescope

An image stabilizer has been inserted into the optical path of the THEMIS solar telescope. THEMIS is a Ritchey–Chretien reflector telescope using an altazimuthal mount and closely tied to its spectrograph. The optical and mechanical design, implementation and system tests are described, and emphasis is put on the complexity of situations that this stabilizer must accept, including the scanning of the solar surface while stabilizing. The current closed-loop crossover frequency of the device is 65 Hz at ??3 dB on all typical solar scenes.     

Gregor@night: The future high‐resolution stellar spectrograph for the GREGOR solar telescope

We describe the future night‐time spectrograph for the GREGOR solar telescope and present its science core projects. The spectrograph provides a 3‐pixel resolution of up to R = 87 000 in 45 échelle orders covering the wavelength range 390‐900 nm with three grating settings. An iodine cell can be used for high‐precision radial velocity work in the 500‐630 nm range. The operation of the spectrograph and the telescope will be fully automated without the presence of humans during night‐time and will be based on the successful STELLA control system. Future upgrades include a second optical camera for even higher spectral resolution, a Stokes‐V polarimeter and a link to the laser‐frequency comb at the Vacuum Tower Telescope. The night‐time core projects are a study of the angular‐momentum evolution of “The Sun in Time” and a continuation of our long‐term Doppler imaging of active stars (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

关于摄谱仪中畸象系统的若干讨论

本文讨论了摄谱仪中若干畸象系统,它们的作用是缩放入射狭缝的象单在高或宽的方向的尺寸,这等效于在狭缝前、后单在子午面内或弧矢面(色散方向面)内改变光束的孔径角,也等效于准直光束单在子午面或弧矢面内缩放光束宽度,在讨论中指出了准直畸象系统优于非准直畸象系统。 在着重讨论和分析准直畸象系统的不同形式时,我们提出了棱镜系统,它具有许多优点,是最为可行的方案。     

Synthetic Aperture Technic in Astronomy Using Slit Aperture Telescope

The interest in a Rotating Slit-Aperture Telescope (RSAT) among other synthetic aperture telescopes is its capability of being easily coupled with a spectrograph, in order to give reconstructed images of an astronomical object as a function of the light wavelength. Each colored image is comparable with the others for fruitful astrophysical applications. The principle of image reconstruction is well known: it consists of the inversion of the set of projections (Radon transform) given by the telescope during its rotation around its optical axis. A full coverage of the two dimensional Fourier plane can be obtained by rotating the SAT. This problem has led to intense developments for medical imaging (tomography). One of the main difficulties in the reconstruction process in space may come from the jitter of the rotation axis of the RSAT. A set of projections uncorrected for this jitter produces very fuzzy reconstructed images. An elegant solution to the necessary phasing between successive projections is proposed which makes use of a small auxilliary telescope, and some numerical simulations are presented. This revised version was published online in July 2006 with corrections to the Cover Date.     

1991年7月11日墨西哥日全食红外光谱观测及初步结果

本文概述１９９１年７月１１日日全食时中国日食观测队在墨西哥ＬａＰａｚ所作的近红外光谱观测情况及得到的初步结果。观测是用一强光力望远镜和一中小色散的光谱仪，配以ＣＣＤ摄象机、图象处理器、微机等组成的探测系统进行的。日全食时，在λ１０７１２－１０９７２波区共摄得极上层光球和色球的无缝光谱４１帧。日面外约１．０９６Ｒ处的有缝光谱３５帧。文中还介绍了拍得的色球、日珥资料概况。     

Rotation cycles of the sector structure of the solar magnetic field and its activity

We study the rotation of the sector structure of the solar magnetic field by using Stanford magnetographic observations from 1975 until 2000 and magnetic synoptic Hα-maps obtained from 1904 until 2000. The two independent series of observations yielded the same rotation periods of the two-sector (26.86 days) and four-sector (13.64 days) structures. We introduce a new index of the solar rotation, SSPM(t). The spectral power density of the sector structure of the magnetic field is shown to exhibit a 22-year cyclicity. The two-and four-sector structures of the magnetic field rotate faster at the maxima of even 11-year sunspot cycles. This phenomenon may be called the Gnevyshev-Ohl rule for the solar rotation. The 11-year sector-structure activity cycles are shown to lead the 11-year sunspot cycles (Wolf numbers) by 5.5 years. A 55-year component with the slowest rotation in the 18th cycle (1945–1955) was distinguished in the sector-structure rotation.     

Investigating the efficiency of the Beijing Faint Object Spectrograph and Camera(BFOSC) of the Xinglong 2.16-m reflector

The Beijing Faint Object Spectrograph and Camera(BFOSC) is one of the most important instruments operating in conjunction with the 2.16-m telescope at Xinglong Observatory. Every year there are~20 SCI-papers published based on observational data acquired with this telescope. In this work,we have systemically measured the total efficiency of the BFOSC that operates as part of the 2.16-m reflector, based on observations of two ESO flux standard stars. We have obtained the total efficiencies of the BFOSC instrument of different grisms with various slit widths in almost all ranges, and analyzed factors which effect the efficiency of this telescope and spectrograph. For astronomical observers, the result will be useful for them to select a suitable slit width, depending on their scientific goals and weather conditions during observations. For technicians, the result will help them to systemically identify the real efficiency of the telescope and spectrograph, and to further improve the total efficiency and observing capacity of the telescope technically.     

白日视宁度监测仪和在抚仙湖的初步观测结果

报导了用南方基地云南天文台太阳差分像运动视宁度监测仪和美国国立太阳天文台的太阳闪烁仪 ,在云南省澄江县抚仙湖老鹰地红外太阳塔选址点进行的对比观测 ,简要地介绍了这两种视宁度测量方法的原理 ,对观测的初步结果进行了分析。