This PDF file contains the front matter associated with SPIE Proceedings Volume 7654, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

During finely grinding the best fit sphere and initial stage of polishing, surface error of large aperture aspheric mirrors is too big to test using common interferometer. Foucault test is widely used in fabricating large aperture mirrors. However, the optical path is disturbed seriously by air turbulence, and changes of light and dark zones can not be identified, which often lowers people's judging ability and results in making mistake to diagnose surface error of the whole mirror. To solve the problem, the research presents wavefront retrieval based on Foucault test through digital image processing and quantitative calculation. Firstly, real Foucault image can be gained through collecting a variety of images by CCD, and then average these image to eliminate air turbulence. Secondly, gray values are converted into surface error values through principle derivation, mathematical modeling, and software programming. Thirdly, linear deviation brought by defocus should be removed by least-square method to get real surface error. At last, according to real surface error, plot wavefront map, gray contour map and corresponding pseudo color contour map. The experimental results indicates that the three-dimensional wavefront map and two-dimensional contour map are able to accurately and intuitively show surface error on the whole mirrors under test, and they are beneficial to grasp surface error as a whole. The technique can be used to guide the fabrication of large aperture and long focal mirrors during grinding and initial stage of polishing the aspheric surface, which improves fabricating efficiency and precision greatly.

Using a spherical mirror of 400mm diameter and 12mm thickness, active supporting technology of thin mirror is researched. The axial support of the mirror is composed of 12 active supports and 3 fixed supports. The force actuator, which is composed of displacement actuator and force sensor, is installed in the active support. The mirror surface is tested by Zygo interferometer. For calibration, each actuator exerts unit force alone, and the surface variation is tested and taken as the response function of the actuator. The response functions of all actuators compose the stiffness matrix. Then the stiffness matrix is used by damped least square method to determine the correction force of each active support. In order to analyze the correction capability of the active supports, 14 Zernike modes of the mirror surface are generated and tested respectively, and 7 modes are selected for correction. Initially, the RMS error of mirror surface is 1.16λ I(λ =0.6328nm)when all actuators exert the same force. After 5 iterations, the RMS error of mirror surface is reduced to 0.13λ, close to the original surface quality.

To realize the fast, efficient alignment of Cassegrain system, the scheme of computer-aided alignment is proposed. The misalignment state of Cassegrain system was simulated in Zemax, corresponding relationship between the misalignments and Zernike polynomial coefficients is analyzed and the misalignment characteristics of Cassegrain system were summarized by Matlab. Finally, the alignment scheme is determined by analysis. In order to verify the scheme, the Cassegrain system was aligned according to the value which was calculated in accordance with the alignment scheme. The result demonstrates that the alignment scheme is feasible to Cassegrain system. Satisfactory results are achieved in applying the scheme of computer-aided alignment to the alignment of 1.2m and 1.8m telescopes.

Phased telescope array, also known as Fizeau interferometer or optical sparse aperture imaging system, collects the beams of each sub-telescope and forms a picture of the object. Due to the decrease in area of collecting light, compared with equivalent diameter telescope, the contrast of phased telescope array in middle and high frequency is low, but both of the phased telescope array and equivalent diameter telescope almost have the same cut off frequency. Therefore a high resolution and clear picture can be restored by post-processing of the blurred picture. There are several methods of postprocessing, nearly all of which are going to deconvolve the blurred picture. Most deconvolution methods are in need of practical point spread function (PSF) or optical transfer function (OTF). However, it is usually hard to obtain a practical PSF or OTF due to the large aperture diameter of system. Even though the practical PSF or OTF can be obtained, the cost for this implementation will be very high for a space-based telescope. Fortunately, the blind deconvolution based on total variation (TV) provides the possibility to avoid this situation, because the TV blind deconvolution is less dependent on practical PSF or OTF, even without any prior knowledge and will preserve the edge information of image. The TV blind deconvolution has achieved great success in many fields and has been studied for decades. However, due to the complexity of PSF, the TV blind deconvolution has not been used in phased telescope array. In this paper, we have investigated the validation of TV blind deconvolution in phased telescope array, and reveals that the TV blind deconvolution is effective in image restoration.

The paper studied error of the finite element numerical values, which was about the large-aperture optical components. Then, a one-dimensional model of beam and a two-dimensional model of square plant had been established, respectively. It calculated the two solutions of FEA and elastic theory in the different unit size. According to the results, it's found that the value of FEA was bigger than the theoretical solution, and the error of the finite element numerical values decreased with the increase of the number of units.

The stressed-lap technique has been proven to be an effective method to meet the challenge of polishing large mirrors with highly aspheric figures. It has the advantage of high material removal and strong natural smoothing tendency over a wide range of spatial frequencies, only round mirrors could be processed with this technology. A solution is put forward in this paper by applying the CCOS (Computer controlled optical surfacing) removing strategy into the stressed lap technology, employing the stressed lap as the removing tool but moving the lap in the CCOS fashion, naming the stressed lap with orbital motion. With the new technology, almost any shape of mirror could be processed, the figuring ability could be improved and the changing rate of the force imposed on the lap turn out to be only 1/6 of the stressed lap with spinning motion based on simulation results, which conducing a lower response requirement of the lap with orbital motion.

For large aspheric optical elements, Computer Controlled Active Lap(CCAL) manufacturing which developed in IOE (Institute of Optics and Electronics, Chinese Academy of Science), have some advantages such as higher manufacturing efficiency, lower middle-frequency and high-frequency errors comparing the fixed lapping technology and CCOS(Computer Controlled Optical Surface) technology. A paraboloid surface of Φ1250mmF/1.5 was grinded by the active lap bonded with ceramic pills, as well as polished will pitch bonded active lap. During polishing processing a null lens was designed to test the paraboloid surface, the final testing data of RMS with ZYGO interferometer reached to 0.027λ(λ=0.6328μm).

There are three main nonlinear elements in the large mirror assemblies, which are screw pretension, adhesive stress and state changes in the assembly process. The optical shape will be influenced seriously by these factors. But the impacts will not be shown in linear analysis results, because as the simplification, these factors have been ignored. The nonlinear analysis method for predicting optical surface deformations resulted from assembly process is discussed in detail. Take a typical mirror support structure for example, the nonlinear analysis model was established. Comparing the calculation results with the optical shape test, it is illustrated that nonlinear analysis is more accurate and closer to the test result. And according to the simulation result, the bowl-shaped depression which was discovered in the test can also be explained reasonably.

Giant Magellan Telescope (GMT) is one of the largest next-generation ground telescopes whose diameter is 25.4m. It has been developed since 2003, and is expected to be finished by 2018. Korea officially joined the GMT project in 2009, and actively participates in the development. KASI (Korea Astronomy & Space Science Institute) and Korean astronomical society are planning several activities to enhance the capabilities in science research. Building a secondary mirror system is another activity Korea wants to develop. A prototype of the GMT secondary is being developed. Developing a spectrograph is another one. In this talk, I will present the plan of Korea's works for the GMT.

A dynamic auto-collimation system for inspecting the performances of optical tracking devices is proposed and analyzed in the paper, which includes a simulation of a moving target and the gimbaled mirror embedded in the optical path of auto-collimation to construct a close loop of measurement. In this system, the gimbaled mirror tracks the movement of simulation target and the auto-collimation gives the tracking deviation and feedback to the system. Static pointing accuracy, response to step movement and dynamic tracking performance of the tracking device under test were measured for the two axes of gimbaled mirror. The researched result shows that the method is effective in indoor inspection of static and dynamic performances of optical tracking devices constituting of gimbaled mirrors and other large angle beam steering devices.

Large size aspherical optic surfaces have gained significant importance and indispensability because of their desirable properties, and the fast growing demand needs urgently efficient and economical fabrication methods. A precision diamond turning machine with rotating tool feed and fast tool servo systems special for turning large asphercial mirrors is introduced, and a method to determine the best-fit sphere for this diamond turning method is also presented. A precise in-site measurement of the processing optical mirror is planned to construct on this machine tool in order to enhance the precision and efficiency, and reduce the production cost. The lateral shearing interferometer is known for being made small and having almost common-path beams that makes insensitive to mechanical vibrations and air turbulence, so it can be very suitable for measurement on the spot.

The utilization of a telescope with a large single aperture is limited by the manufacturing technique, cost, volume and weight of a monolithic mirror. In order to solve these problems, the technology of the segmented synthetic aperture was introduced. The primary mirror of a large segmented synthetic aperture telescope consists of several segmented mirrors, whose misalignment errors make the wavefront change drastically and influence the MTF of the optical system badly. The wavefront coding technology (WFC) is an innovative technology that joints the optical design and digital image processing together. By adding a phase mask close to the pupil of an optical system and modulating the wavefront, the WFC system becomes very insensitive to defocus and other aberrations based on defocus. The theoretical analysis of characteristics of the WFC system was done in the form of PSF. The application of WFC to a segmented three mirror anastigmat (TMA) was presented. A space telescope with an effective focal length as 40m, a F number as 10, a field of view as 0.5°x0.05° was designed, whose primary mirror consisted of seven segmented mirrors. The influence of defocus and misalignment errors on the telescope was discussed. The imaging process of the WFC system and following image restoration were simulated. As a result, sharp images were obtained and the large segmented synthetic aperture telescope had looser misalignment tolerance and extended depth of focus.

"Off-axis three-mirror anastigmatic telescope without middle image" and "off-axis three-mirror anastigmatic telescope with one middle image" are both popular in space remote sensing. Working tolerances are analyzed deeply in both configurations. Compared with "off-axis three mirrors anastigmatic telescope without middle image", "off-axis three mirrors anastigmatic telescope with one middle image" has bad working tolerances.

This paper focuses on thermal effects, which caused by environmental temperature changes, on coaxial reflective space telescope and its solution. Curvature radius and center thickness of optical elements, and the space distance between optical elements may be changed by thermal effects. And the optical performance of the telescope may be impacted. Based on the analysis of thermal effects on coaxial reflective space telescope, athermalized design techniques are emphatically presented, the advantages and the disadvantages of the three athermalizations used currently are compared in the paper. The feasibility and effectiveness are verified by an example of a cassegrain space telescope.

With the development of the technology of autocontrol, telescope, computer, network and communication, the control system of the modern large and extra lager telescope become more and more complicated, especially application of active optics. Large telescope based on active optics maybe contain enormous force actuators. This is a challenge to traditional control system based on wired networks, which result in difficult-to-manage, occupy signification space and lack of system flexibility. Wireless network can resolve these disadvantages of wired network. Presented control system of telescope force actuators based on WLAN (WFCS), designed the control system framework of WFCS. To improve the performance of real-time, we developed software of force actuators control system in Linux. Finally, this paper discussed improvement of WFCS real-time, conceived maybe improvement in the future.

The primary mirror of large-aperture telescope is an important component of telescope system. The surface figure error of the primary mirror is a critical factor affecting the imaging quality of telescope system. With the augment of primary mirror aperture, the surface figure error of the primary mirror is affected by many factors, such as gravity, thermal deformation and so on. The factors that influence the surface figure error of the primary mirror are considered and analyzed roundly according to technical requirements of optical system. So the feasible project is researched on the lateral support structure of large-aperture telescope primary mirror. The primary mirror support system of large-aperture telescope is composed of axial support and lateral support. In traditional telescope, the contribution of lateral support to surface distortion is less than axial support. With increase of diameter to thickness ratio, lateral support is becoming more complicated and important than before. Lateral support is a key technology the same as axial support for the large-aperture telescope primary mirror. With the foundation of analysis, comparison and conclusion of related literature and monograph, according to primary mirror supporting principle of the large-aperture telescope. Lateral support methods, the influence of the primary mirror surface figure error due to primary mirror lateral support and lateral support structure of primary mirror are analyzed.

In ground-based optical detection system, when large aperture primary mirror in a different pitch angle detection, the surface shape error of primary mirror is affected by its weight deformation, and the surface shape error of primary mirror is one of the key factors affecting imaging quality. The primary mirror support system, including axial support and radial support, and the axial support is main factor affecting the surface shape error of primary mirror, the position and number of axial support is very important for surface shape error of primary mirror. The support technology of Φ1.2m primary mirror was studied detailedly in this paper, the parameterized model of primary mirror was built based on ANSYS, the relationship between the surface shape error of primary mirror and the ratio of its diameter to thickness was analyzed, the axial support was optimized, and the support-ring number, support-ring radius and support point position of axial support were optimum designed. The result of analysis showed that the Root-Mean-Square (RMS) value of the surface shape error of primary mirror was 1.8 nm, when the primary mirror pointed to zenith, met to the design need of the optical system, and the axial support system was verified.

The precise tracking technology is wide used in astronomical instruments, satellite tracking and aeronautic test bed. However, the precise ultra low speed tracking drive system is one high integrated electromechanical system, which one complexly electromechanical design method is adopted to improve the efficiency, reliability and quality of the system during the design and manufacture circle. The precise Tracking Bed is one ultra-exact, ultra-low speed, high precision and huge inertial instrument, which some kind of mechanism and environment of the ultra low speed is different from general technology. This paper explores the design process based on complex electromechanical optimizing design theory, one non-PID with a CMAC forward feedback control method is used in the servo system of the precise tracking bed and some simulation results are discussed.

Thanks to the dry climate condition and high atmospheric transmittance, the Antarctic area becomes the ideal location for astronomy observatories. But the construction and operation of the astronomy telescopes in the Antarctic encounter many challenges due to the extremely cold weather. One of the most important themes of the astronomy arena is to research and develop the Robotic Telescope (RT) under extremely adverse environmental condition in the Antarctic area. This paper provides the basic concepts and components of the RT, indicating that the RT is an intelligence integrated control system consisting of telescope control system (TCS), environment control system (ECS), temperature control system (PCS) and building control system (BCS) and so on. The paper also presents a simulation model for the minim system of the RT, the TCS simulation model, on the basis of which the authors explore the feasibility of the RT in the Antarctic. The operations of the TCS are divided into several steps. This simulation model, encoded by MFC under Visual C++ 6.0, is developed to simulate the operation procedures of the TCS, including the initialization, self-check, calibration, open, focusing, observation, data-recording, data-preprocessing, closing, standby and other procedures. In the view of the features of no-man-on-duty, this paper particularly proposes the process of error-locating, errorcorrecting, error-recording under fault conditions. And the authors implement the watchdog to carry out this process automatically by the computer in case of failure. Through the simulation, the feasibility and security of the RT is proved effectively, thus providing important basis and reference for the smooth operation of the RT under extreme environment.

Metal is an early telescope mirror material, it was later replaced by glass which has lower thermal expansion coefficient. However, for observing the sun, these glass materials in the primary mirror are affected by the sun's intense radiation, its temperature rises rapidly, but which conducts heat slowly. The temperature difference between mirror and ambient air is so large that causing the air turbulence which has affected the observation precision. While the metal material has better thermal conductivity characteristics, it can greatly improve the problems caused by air turbulence. This paper analyzes the characteristics of the various mirror materials, and then makes a rust-proof aluminum alloy 5A05 as the mirror substrate material. For the major deficiencies of the soft aluminum surface which is not suitable for polishing, this paper presents a method of electroless nickel plating to improve its surface properties. After the mirror go through a thermal shock, the upper and lower levels of metal CTE don't match with each other, which leads to mirror deformation and warping. The bimetallic effect has been illustrated by the theory of beam element and give a result of elementary approximated. The analysis shows that the displacement deformation of the upper and lower layers of metal which is caused by thermal shock is smaller when the CTE is closer. In the experiments, a spherical aluminum mirrors with the substrate of 5A05 aluminum alloy, diameter of 110mm, the radius of curvature of 258.672mm is manufactured in classical technique. And it ultimately achieves optical mirror-polished precision. Besides, the long-term thermal stability experimental study of the aluminum mirrors proved that Al-infrared solar telescope primary mirror meets the needs of the long-term observation during use.

High-quality optical elements are very important in modern technology; in particular top-quality aspheric optical elements. The concept of an extremely large ground based telescope is a significant technical challenge particularly for the manufacture of the optical components necessary to realize the very demanding performance. Extremely large ground based telescopes require many high-quality, large-diameter optical elements for their construction. The method of optical polishing, using an ultra precise bonnet, is based upon the use of computer controlled fabrication of an optical surface. A bonnet filled with air is used as a precise polishing tool which is flexible and can adapt itself well to the shape of the part, compared with other polishing methods. As with other polishing techniques the edge quality is a key factor affecting the performance of the optical element. In this paper, the effects of edge performance are analyzed, and three compensating techniques are discussed. It is demonstrated that, good edge control can be achieved by using a special removal function applied to the polishing process. Some experimental results are shown and a consecutive polishing process is described.

A scheme of combining technology of orthogonal cylindrical lens array (OCLA) and polarization control plate (PCP) is introduced to improve target irradiation uniformity in laser fusion. The feasibility of the scheme is also analyzed by detailed two-dimensional simulation. It shows that a focal pattern with flat-top and sharp-edge profile could be obtained with an OCLA, while interference stripes inside the pattern are smoothed out by the use of the polarization control plate (PCP) technique. Moving the target slightly from the exact focal plane of the principal focusing lens can eliminate middle-scale-length intensity fluctuation further. And a well-irradiated laser spot with small nonuniformity and great energy efficiency can be obtained in this scheme.

Wavefront control technology and imaging experiment are introduced for a segmented mirror SAO system with deformable sub-mirrors. This system is a RC style with 300mm aperture, 4.5 F#, ±0.4°FOV, 0.45~0.75μm wave band, and diffraction-limit design MTF. The primary mirror is composed by three sub-mirrors, with parabolic shape, and each deformable sub-mirror has 19 actuators to control and keep the surface shape, and 5 actuators to align sub-mirrors location in 5 degree of freedom. Interferometer is used to feed back and control exit wavefront error, and base on measurement and finite element analysis, location and quanitity of actuators are optimized, making the surface shape and misadjustment errors interact and compensate each other, and the synthetic system exit pupil wavefront error is controlled. The integrated exit pupil wavefront errors are gotten by ZYGO interferometer, and central FOV is 0.077λRMS, and edge FOV is 0.093λRMS. At the end, an imaging experiment is executed, and good results are obtained, which proves, the deformable sub-mirrors have the ability to meliorate alignment and the latter can retroact the former, and this relationship iterate make system exit pupil wavefront error convergence and improve segmented mirror SAO system imaging ability.

The azimuth bearing schemes in typical large Alt-azimuth telescopes, especially the 3.5-m APO telescope and the 4.1-m SOAR telescope were analyzed. A scheme of high-angular contacted thrust ball bearing integrated with a radial ball bearing was put forward. According to the Hertz contact theory, the corresponding parameters were designed for engineering application. The static performance parameters, within the range of 60° ~ 85° original contact angle were calculated. Compared with the traditional plane thrust ball bearing, the results shows that the high-angular (α>80°) contact thrust ball bearing has more benefits at bearing strength and rigidity for large telescope. The Φ1500mm diameter prototyping bearing shows good performance, including the axial jitter is 0.009mm, the radial jitter is 0.006mm, the maximum starting torque without load is 30N•m, and the load capacity is more than 30t, which offers advanced technique path for the buildup of the high precision azimuth shafting and the whole telescope system.

When uniformly distributed circular load is applied on ultra thin circular mirror and the outer edge of the mirror is clamped, completely theoretical derivations of response function are derived. Lots of simulations are also made. Results show the size of the distributed load's area do not immediately decided the whole shape of the mirror when the intensity of the distributed load remains constant. And the size of the distributed load's area only obviously changes the deformation of the center point of load gravity. If the size of the area is bigger, the deformation of this point is bigger, and vice versa. Meanwhile, the theoretical analysis method is also used to other shapes of the uniformly distributed load, such as sector, rectangle or triangle.

There are several kinds of complicated pupil telescopes including sparse-aperture telescopes and segmented-aperture telescpoes. Misalignment or misfigure of these segments or subapertures results in wavefront errors which degrade the imaging quality. Wavefront control for complicated pupil space telescopes is necessary in the fabrication. Three kinds of techniques of wavefront control are introduced. These include phase diversity, in-focus PSF optimizer and coarse phasing with white light interferometry. The principles of three kinds of techniques are illustrated and compared. The performances as wavefront sensors are also introduced. Phase diversity is a combined collection and post-processing techique to infer unknow phase aberrations from image date. In-focus PSF optimizer is a parameter estimation process in which a computer-generated model PSF matches an observed PSF. Coarse phasing with white light interferometry uses the features of the white light PSF formed by complicated pupil space telescopes to detect and correct the piston between segments or sub-apertures. It is obvious that different methods of wavefront control have different characteristics. In order to solve the optical alignment for complicated pupil telescopes, different methods of wavefront controls are selected to complete the correction of errors based on the different situation.

The existence of contaminated mirror in infrared telescope system not only reduces the contrast between objects and background, but also leads to the nonuniformity of the flux distribution of stray radiation on detector, resulting in great difficulty in obtaining and analyzing the target signal. In this paper, taking Cassegrain telescope as a typical example and using the optical analysis software, i.e., ASAP, the three-dimensional simulation model has also been built up. The self-generated thermal radiation flux and the flux distributions of stray radiation on the image plane have been simulated when the primary mirror under two cases, i.e., clean and local area contaminated. The influence of the size and position of the contaminated area on the uniformity of the flux distributions of stray radiation has been focused on discussion. The radiation flux and the flux distributions of stray radiation have been employed to evaluate the stray radiation performance of the system. The results indicate that the local area contamination on mirrors could change the uniformity of the flux distributions on the image plane and also degrade the stray radiation performance of the system, resulting in the influence on the detection and identification of the target. Consequently, it is of critical importance to keep the surface of optical elements clean, especially to avoid local area contamination on optics.

In this paper, simulation model of infrared optical systems with Cassegrain structure has been built up, and the stray radiation analysis has been performed. The contributions of each component to stray radiation of infrared system and the corresponding optical path of stray radiation have been studied in detail. On this basis, the flux distributions of the stray radiation of the major contributors on the detector have been simulated, and the uniformity of the flux distributions has also been discussed. In order to suppress the stray radiation of the system, the corresponding methods have been adopted according to different paths of the stray radiation. Finally, the flux of stray radiation and the uniformity of the flux distributions on the detector before and after taking the suppression measures have been compared and analyzed. The results indicate that the methods for suppressing the stray radiation according to the characteristics of stray radiation source can effectively improve the stray radiation performance of the system, resulting in the improvement of the detection performance of the system.

Infrared telescopes are often required to work in a complex thermal environment. A long time of daytime heating will cause the temperature of the telescope dome and the surrounding facilities different from the ambient air during the night. Different levels of temperature controlling and the accuracy of forecasting will lead to the temperature departures between the components in the system. Furthermore, the contaminated particles settled on the optical elements will change the optical characteristics of the optical elements. All of these factors will degrade the stray light performances of infrared telescopes. In this paper, taking Cassegrain as a typical example and using the optical analysis software, i.e., ASAP, the three-dimensional simulation models of the infrared telescope and the dome has been built up. On this basis, the stray light performances and the variation of the systems have been simulated and analyzed for the different cases of the different coating for the dome, the change of the temperature of primary and ambient, as well as the existence of the mirror contamination. The effective emissivity has been introduced and the stray light performance of the systems has been evaluated. The results indicate that the contaminated particles settled on the optical elements will degrade the system performances significantly, whereas the influences of other factors are relatively small. Therefore, it is of great importance to focus on the contaminated particles settled on the optical elements to adopt proper methods to improve the stray light performances of infrared telescope systems.

Multi-band IR data of the space object can be used in the fields of object identification and space surveillance. The radiation characteristics of the object can be obtained by analyzing these data. These characteristics include temperature, area, emissivity, absorptivity, reflectivity, and temporal trends. The infrared radiation temperature of the space object is an important characteristic from which the object's working state in orbit can be judged. We apply the method of measuring the spectral distribution of the object and fit the data to the Planck formula to determine the temperature. In order to improve the precision of measuring temperature on the space object, we optimize the centric wavelength and the bandwidth effectively. Also, we use a simple program to implement temperature measurement.

Dispersed Rayleigh Interferometry has been verified a potential way to co-phasing segmented mirror in orbit using natural star as beacon. Measurement error caused by background star around beacon is analyzed under specific system parameters, and tolerances of magnitude difference in two orthogonal directions are also presented. To achieve 10nm / 20nm accuracy, minimum magnitude difference of background star and beacon star is about 2.5M / 1.7M. Furthermore, it is proved by calculating more than 6000 positions of background star distributed in an area about twice larger than the Airy disk in diameter.

This paper describes a pentaprism scanning combined with sub-aperture stitching interference method to test large aperture optical system wave-front. This method uses pentaprism scanning and interferometer testing sub-aperture optical system wave-front, after testing all the sub-aperture wave-front and then using average error stitching algorithm to reconstruction full-aperture optical system wave-front. It makes use of the pentaprism easily to adjust and interferometer's high-precision characteristic. Analyzed the mechanical precision of turntable and electric guide, when the turntable sway angle is less than 8', location accuracy is less than 1.194' and the electric guide linearity is less than 8'location accuracy is less than 83.3μm, can meet the testing requirements. We used 40mm sub-aperture testing 312mm full aperture wave-front PV is 0.2197λ and RMS is 0.0536λ. Compared the stitching results with Zygo interferometer directly full aperture testing verified the accuracy of the method and provides a new idea for testing a large aperture optical wave-front.

The performance of a remote sensing imaging system is often degraded by wave-front aberrations that introduced by different sources such as the atmospheric disturbance and the aberrations of the optical system. A new remote sensing imaging system based on phase diversity (PD) method which does not need a priori information and has simple configuration and high reliability, is designed in this paper. The process of image reconstruction based on PD method is simulated according to the characteristics of space and aerial remote sensing imaging system. The index of energy gradient function of the image obtained by using PD method is improved greatly. The simulation results prove that PD method has special potential to improve the image quality in remote sensing imaging system.

Silicon carbide ceramic is a prospective candidate for the next generation space telescope with a large-scale reflector. In order to reduce the cost of the fabrication of complex shaped component, the joining technology of SiC ceramic is investigated. In this work, SiC ceramic was joined by reaction bonded technology using SiC green preforms successfully. SiC green preforms were fastened together by epoxy resin and joined during the process of one-step Si infiltration. The microstructure and composition of SiC substrate ceramic and the joint is homogeneous and there have no micro-cracks or defects in the joint. The interface reaction layer become smaller and even disappears with carefully surface grinding of the SiC green preforms. The surface roughness of the joined SiC in the area of the joint is 0.95nm rms and there has no significant difference in the surface roughness of the joint area and SiC substrate ceramic. The bending strength of the joined SiC is about 300MPa and the crack occurred inside the SiC substrate but not in the joint. The most important advantage of the method is the joining of SiC ceramics was achieved via one-step Si infiltration process and the joints are homogeneous with the substrate, which is economical and effective. The mechanical and optical properties of the joined SiC can satisfy the requirement of the large-scale telescope in many astronomical instruments.

Since Deb's experiment in 1973 on the electrochromic effect, transmissive electrochromic films exhibit outstanding potential as energy efficient window controls which allow dynamic control of the solar energy transmission. These films with non-volatile memory, once in the coloured state, remain in the same state even after removal of the field. The optical and electrochemical properties of electrochromic films using magnetron sputter deposition tungsten oxide thin films and vanadium oxide doped tungsten-vanadium oxide thin films on ITO coated glass were investigated. From the UV region of the transmittance spectra, the optical band gap energy from the fundamental absorption edge can be determined. And the Cyclic voltammograms of these thin films in 1 mol LiClO₄ propylene carbonate electrolyte (LIPC) were measured and analysed. The anode electrochromic V₂O₅ doped cathode electrochromic WO₃ could make films colour changing while the transmittance of films keeped invariance. These performance characteristics make tungstenvanadium oxide colour changeably thin films are suitable for electrochromic windows applications.

Based on the analysis of a 1.2m-diameter active primary mirror system under gravity load, several performance parameters of actuator are reported in this paper. The actuator is demanded to satisfy the active optics correction, support the axial load of primary mirror, and compensate the deformation of axial supports. The quasi-Zernike polynomials are employed to fit the maximal allowed surface error of telescope to compute the force accuracy of actuator. Moreover, the axial load and deformation of primary mirror system is analyzed by using the finite element (FE) method. Through the above procedures, the performance parameters, such as force range, force accuracy, axial stroke and displacement resolution, are obtained.

The paper presents a closed-loop adaptive optics (AO) system that uses two deformable mirrors (DMs) to compensate for both amplitude and phase fluctuation of output beam. The validation and feasibility of an AO technology using two DMs has been verified experimentally. Consequently, the quality of laser beam in the near field is improved and the far field image is close to diffraction limit in the experiment. The Strehl ratio (SR) of far-field image increases from 0.837 using conventional AO technology to 0.952 using the two DMs AO technology.

Five-hundred-meter Aperture Spherical radio Telescope (FAST), will be the largest radio telescope in the world. The dynamic surveying of the laser total station is one of the key technologies of FAST. So time-delay analysis for dynamic surveying is very essential for the building of FAST. One Leica laser total stations are employed to measure position of SMR. Laser tracker API is high-precision measuring device, and is used to monitor the spatial position of SMR in the real time. Two kinds of measuring data were sent to the same measurement computer, so these data have the same time-tag. Large numbers of experiment data were obtained, and there are many questions to be answered by this experiment. The delay time was found, the dynamic measurement precision of laser total station was test. The results of time-delay examination indicate that time-delay influence great the measurement and control precision. In spite of total station's dissatisfactory aspects, e.g. time-delay, sample rate, the total station measurement system can meet the requirement of the model. For higher precision, we need to take steps for eliminating time-delay. With the deepened of study, the laser total station will play an increasingly important part in the FAST.

In some applications, especially in satellite or airborne cameras, the field of view (FOV) of imaging systems is limited by the format size of the image sensors. An optical butting system using optical butting technology is proposed to overcome such constraint. In this system the optical image is divided into four parts by a beam splitter, each of the four sub-images is received by a corresponding image sensor. The image characteristics of such optical butting system are investigated. To do that, the optical butting system is divided into four sub-imaging systems. An equivalent imaging system of the sub-imaging system is set up. Point spread functions (PSF) of the optical butting system are obtained by combining PSFs of the four sub-imaging system. We use the PSF amd MTF (Modulation transfer Function) to analyze the imaging characteristics of the optical butting system. The imaging characteristics can be used to decide the sub-image combining strategy and guide the design of the optical butting system.

As Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) project was completed successfully, indicating the key technology of active optics has been mastered by the Chinese astronomical community, experts of Nanjing Institute of Astronomical Optics and Technology (NIAOT), builders of this project, started to consider how to use the technology developed in large optical telescope such as LAMOST to improve the performance of millimeterwave / sub-millimeter-wave telescope. In order to do more research work about active optics of millimeter submillimeter band and improve the performance of Delingha 13.7m millimeter-wave telescope, researchers of NIAOT intend to upgrade the reflect panel accuracy of this telescope. This paper will introduce the preliminary work of the accuracy-upgrading task, numerical simulation of the 13.7m telescope. In this presentation, the primary reflector finite element model (FEM) construction, gravity and thermal deformation, and modal analyze are described. The result shows that the gravity and thermal distortion of the reflector are contributed mostly by the back-structure and the active support for the panels is very necessary to restrain this kind of distortion.

Active optics is one of the key technologies for constructing modern large telescope. It's necessary to study the performance of an active optics system theoretically in advance. In this paper we built a 1.2 m active thin-mirror model with 36 axial supports and 3 lateral supports. In order to ensure the active optics system and select appropriate force actuators, we carried out following analyses through FEA: the ability of the active optics system to duplicate the first 15 Zernike modes and the first 15 natural resonance modes; mirror deformations before and after active force corrections under gravitational loads; the maximum stresses of the mirror while fitting Zernike modes of 1 micron PV amplitude; requirements of the force accuracy and the maximum load for the force actuators. Through above analyses over the theoretical performance of the 1.2 m active thin-mirror, it can be concluded that: the support system is effective to maintain the mirror surface; the maximum stresses of the mirror while fitting aberrations are within the allowable stress of the glass material; the force resolution is about 0.5 N and the maximum load for the force actuators is about 400 N. As a result fundamentals are set up for constructing a practical active mirror.

Pulse infrared laser launched by the prepositional laser fuse system reaches the target first. Laser echo pulse signal then arrive the surface of photodiode laser detection receiver, and penetrates through the boundary layer - shear layer - shock wave - atmosphere - shock wave - shear layer - boundary layer under supersonic velocity, finally, focuses on the photosensitive surface. As shock wave has an effect on the prepositional laser fuse in the optical path, a great deviation has been brought between distance determining methods on static state and in the course of the actual flight. In this paper, a model of the shock wave's influence on the prepositional laser fuse's optical distance under supersonic velocity is presented. Based on a certain projectile, the optical path difference is analyzed. The optical path differences under different projectile velocities are figured out with the MATLAB software, which will provide a feasible error analysis method for the exploration of laser fuse or laser weapon under supersonic velocity.

The optical systems with large collecting aperture and high resolution are the future development directions of optical systems on orbit. The primary mirror of optical system is segmented for its advantages in reducing the difficulty of manufacturing to achieve high imaging resolution. Once on orbit, it needs to correct the misalignment errors in optical system introduced by the effect of various factors. The phase retrieval based on quasi-Newton method nonlinear optimization is proposed to sense the wavefront aberration induced by segmented mirrors in the optical system. And the BFGS method is utilized to seek the optimum value of wavefront aberrations. Then the different defocus impacted on detection accuracy is analyzed. The result of the simulation experiment indicated that once select the suitable defocus, the phase retrieval method can control the wavefront detection error less than 6%.

Research and manufacture of large aperture and lightweight telescope is urgently needed with the development of space optical system and the requirement for high resolution, and becomes one of the main tasks in space science area in future. The membrane mirror with a substrate of flexible film has characteristics of lightweight, compact-deployable and low cost compared to the traditional one and it is prospected to be applied in future large space optical systems. The surface shape control is one of the key technologies for the manufacture of membrane mirror. Based on the previous research works carried out in our lab, the surface shape of membrane mirror applied by non-uniform load is theoretically analyzed and simulated in the membrane mirror's surface shape control system in this paper. The construction of the system and the realization of the functions are described in detail. The analysis and simulation of surface shape control of membrane mirrors with 300mm aperture and different F numbers are performed applied by both non-uniform load and uniform load in the control system. The results of the simulation show that the RMS wavefront error of the membrane mirror under non-uniform load can be controlled and improved in two orders of magnitude comparing to that of the membrane mirror under uniform load, which is prospected to be a viable method for the design and manufacture of large aperture and lightweight membrane mirror with high surface accuracy.

Silicon carbide (SiC) is a new type candidate material for large-scale lightweight space mirror. Its low thermal distortion, high stiffness, fine optical quality and dimensional stability, make SiC an ideal material for large space born telescope. Since ten years Changchun institute optics, fine mechanics and physics (CIOMP) has developed reaction bonded SiC (RB-SiC) technology for space application, and can fabricate RB-SiC mirror with scale less than 1.0 meter for telescope. The green body is prepared with gel-casting method which is an attractive new ceramic forming process for making high-quality, complex-shaped ceramic parts. And then unmolding, drying, binder burning out, reacting bonded, the RB-SiC can be obtained. But with the development of space-born or ground telescope, the scale of primary mirror has exceeded 1.0 meter. So CIOMP has developed an assembly technique which called novel reaction-formed joint technology for larger RB-SiC mirror blank. The steps include joining of green bodies with mixture comprised of SiC particles and phenolic resin etc, firing, machining and sintering. Joining the Φ1.2 meter RB-SiC mirror blank by the novel reaction-formed joint technology. And testing the welding layer's performance, the results show that the thickness of 54-77μm, the microstructure and thermal property can be comparable to the substrate and the mechanical property are excellent in bending strength of 307MPa.

The composite structures were fabricated by wrinkle formation and optical lithography. Complex and ordered wrinkle patterns are spontaneously created on metal thin films thermally deposited onto elastomeric polymers owing to mismatch of thermal expansion. In the experiments, a thin film of Au with 20-50 nm thick was deposited by ion sputtering on the surface of polydimethylsiloxane (PDMS) substrates. To modulate wrinkle patterns regularly and uniformly, optical lithography was used to fabricate given structures in Silicon wafers, and these structures were transferred onto PDMS substrates by replica molding. In the process of wrinkle formation, the configuration on the PDMS substrates could effect or regulate wrinkle formation, and so the composite structures effectively integrate the lithographic and wrinkle patterns. These unique structures have potential application in optical devices, sensors and actuators.

Any kinds of tiny vibration of machine tool parts will have a great influence on surface quality of the workpiece at ultra-precise machining process of aspheric surface. At present the major way for decreasing influence of vibration is machining compensation technology. Therefore it is important for machining compensation control to acquire and transmit these vibration signals effectively. This paper presents a vibration monitoring system of aspheric surface machining machine tool based on wireless sensor networks (WSN). Some key issues of wireless sensor networks for vibration monitoring system of aspheric surface machining are discussed. The reliability of data transmission, network communication protocol and synchronization mechanism of wireless sensor networks are studied for the vibration monitoring system. The proposed system achieves multi-sensors vibration monitoring involving the grinding wheel, the workpiece and the workbench spindle. The wireless transmission of vibration signals is achieved by the combination with vibration sensor nodes and wireless network. In this paper, these vibration sensor nodes are developed. An experimental platform is structured which employs wireless sensor networks to the vibration monitoring system in order to test acquisition and wireless transmission of vibration signal. The test results show that the proposed system can achieve vibration data transmission effectively and reliability and meet the monitoring requirements of aspheric surface machining machine tool.

With the development of aeromechanics, large light reflector that satisfies the diffraction of light becomes the dominant object of the optical operator. The assumption of designing reflector with organic membrane with reflecting layer plated emerges as the times require. based on an analytical solution of Poisson's equation and careful analysis of forming method, the paper puts forward a conclusion that multi-electrode controlled electrostatic stretching membrane mirror is a better way than single-electrode controlled electrostatic stretching membrane mirror and also gives a preliminary comparative analysis of these two method.

The bond stress is analyzed when the optics were attached to their mounts with high strength adhesive in space camera. The model was founded that a circular planar reflector supported by one, three, six or twelve adhesive points, which evenly distributed on different circles. The surface deformation of reflector is mainly caused by the shrinkage after solidity. The functional relation was deduced between the bonding force of the reflector and the characteristic dimension of the adhesive spot using piecewise function, and then analyzing the RMS error of no gravity assuming that the adhesive spot is fixed connect to the reflector using Nastran. The analytical RMS error was the aberration which added by solidification of adhesive. The calculation result is in good agreement with the experiment results. This analyzing method will be useful for the microstress clamping of high performance reflector system for application in space optical systems.

We present the wavefront error budget and optical manufacturing tolerance analysis for 1.8m telescope. The error budget accounts for aberrations induced by optical design residual, manufacturing error, mounting effects, and misalignments. The initial error budget has been generated from the top-down. There will also be an ongoing effort to track the errors from the bottom-up. This will aid in identifying critical areas of concern. The resolution of conflicts will involve a continual process of review and comparison of the top-down and bottom-up approaches, modifying both as needed to meet the top level requirements in the end. As we all know, the adaptive optical system will correct for some of the telescope system imperfections but it cannot be assumed that all errors will be corrected. Therefore, two kinds of error budgets will be presented, one is non-AO top-down error budget and the other is with-AO system error budget. The main advantage of the method is that at the same time it describes the final performance of the telescope, and gives to the optical manufacturer the maximum freedom to define and possibly modify its own manufacturing error budget.

The 127-element adaptive optical system, which consists of a tracking loop with a tip-tilt mirror, a tracking system and a tracking processor, and a wavefront correction loop with a 127-element deformable mirror, a Hartmann-Shack wavefront sensor, and a wavefront processor, had been developed and integrated into the 1.8m astronomical telescope in September 2009. The First observations on the high resolution imaging for the stars had been done from September 23 2009 in the first light to March 2010. In this paper, the 127-element adaptive optical system for 1.8m telescope is described briefly and the star observation results in the first run are reported. The results show the angular resolution of the system can attain or approach the diffraction limit of 1.8m telescope at I band (700nm-1000nm) and J band (1000nm-1700nm).

In the course of space camera observation, the ground target and observing condition are changing all the time, so the light radiance in space camera entrance is different. In order to get appropriate exposure even though ground target is different, we need to analyze the relationship between observing condition and exposure value of space camera. The purpose of this paper is to propose a method to calculate exposure value of space camera according to type of ground target and observing condition. Atmosphere radiative transfer soft PcModWin is developed by Ontar Corporation, USA. Using PcModWin, we can calculate atmospheric transmittance, solar and atmospheric radiance when solar zenith angles, atmosphere models, atmospheric aerosols and atmospheric visibility are different according to variation of observing condition. The target radiance in space camera entrance can be calculated by multiplying ground target radiance by atmospheric transmittance. Adding atmospheric backscattering radiance and target radiance in camera entrance together, we can get total irradiation in camera entrance. Then according to camera aperture value and lens transmittance, we can calculate irradiance of image plane. Finally, by multiplying with exposure time of camera (integral time for TDI-CCD), the exposure value of space camera can be acquired. We established the relationship between ground target, observing condition and exposure of space camera. When the ground target, observing time or weather condition is different, we must set appropriate camera parameters if we want to take qualified photos. This relationship is useful for radiometric calibration in laboratory.

Large optical mirror is a direct and effective way to improving relevant optic system resolution. However, along with mirror size improving, mirror weight increases as exponentially. So mirror lightweight is the key technology for large optical mirror. Moreover as optical surface size increasing, it is hard to control temperature gradient on mirror surface. So analyzing mirror lightweight method, in view of temperature grade distribution on mirror reflecting surface, is more advantage for large mirror application practically. Starting from a large SiO2 primary mirror, the papers introduce temperature analysissitus and mechanics analysissitus to discuss large mirror lighting weight method in view of mirror excellence surface shape quality, regarding temperature gradient distribution on mirror reflecting surface as state function, minimizing mirror weight as object function, Zernike polynomial coefficient as describing optical aberration distribution on mirror surface. From the analysis results, with regard to classic lighting form, papers set up composite radiate lighting form, which is propitious to temperature transferring, improves mirror surface mechanical stiffness and reduces mirror effectual surface density in addition. Appling the lighting form, the lighting rate is less than 70 percent, and the PV value less than λ/5(λ=632.8nm), RMS of mirror surface shape less than λ/20, temperature gradient under 0.001k/mm. From analysis results, it can conclude that this lighting method in view of controlling mirror temperature distribution can reduce large mirror effectual surface density, and control temperature distribution effectively, which promotes large mirror surface temperature controlling technology and supplies technique support to extend large mirror application space.

Exact constraint design can control the interrelation of the components by ensuring the number of the constraints being equal to the number of the degrees of freedom needed. The kinematic mounts which is a point contact linkup structure are the representative structure of exact constraint. It has μm orientation accuracy and 20nm relocation accuracy with low cost. According to the conception and design rule of the kinematic mounts the paper introduces its material choice, stability estimation and accuracy analysis. Two kinds of kinematic mounts sample (upside down and side hang) are designed that can be applied in the large aperture mirrors of ICF (Inertially Confined Fusion, ICF) facility. Mirror mounts of the samples are modularized LRU (Line Replace Unit, LRU). It can provide accurate allocated and relocated accuracy by adopting the kinematic design. Theoretical analysis, accuracy test of relocation and mechanic test of the samples are processed. The sample's maximal angle error of the two samples are less than 2" (design request less than ±40") and its relocating angle error less than 2.3"; (the upside down Sample) and 6.2" (the Side-hang Sample).

To prove the concept of the optical butting method which is used to extend the field of view of an imaging system, we have built a prototype camera. In this camera, the optical image is divided into four parts each of which is received by a corresponding image sensor. In this paper, we present an approach which is capable of compositing the four image parts to form a full image. The response function of the camera is estimated so that we can get a linear camera response. The homography matrices between the four image parts are computed using a feature based image registration method. Vignetting artifacts are removed by vignetting correction factors. Finally, a gradient based image stitching method is proposed to remove the intensity inconsistency.

With the resolution of space optical remote sensor getting higher, the aperture of the primary mirror has been becoming larger correlatively. The requirement of the plane precision has also become higher. The manufacturing and testing of space optical remote sensor primary mirror should be under more critical status which is different from the mirror on the ground, especially for the primary mirror aperture that is larger than 1 m. This paper compares the differences of testing and manufacturing status between the primary mirror on space optical remote sensor and on the ground. A support method of large aperture primary mirror manufacturing and testing has been released, which is to carry out multiplediscrete support on the back of the mirror by controlling the support stress. The results indicates that this method could reduce the plane error of the primary mirror brought by its self weight effectively by finite element simulation when the mirror is being polishing, so as to satisfy the design and use requirement of the primary mirror.

Concave aspheric mirror with large aperture can be manufactured and tested by Offner optical system. In order to manufacture and test a concave aspheric mirror with a aperture of 500mm diameter, firstly the formula of compensating system with single lens is deducted based on the third-order aberration, secondly the initial configuration of Offner optical system is calculated with formula, field lens is also added to balance the optical system, then the data of initial configuration is optimized by optical software ZEMAX, the final result of Offner optical system with single compensating lens is obtained after optimization. With the same principle, the formula of Offner optical system with double compensating lens is deducted, the initial configuration of Offner optical system is also calculated with formula, so the final configuration of double compensating lens system is obtained after optimization. Finally Offner optical system with double compensating lens is selected to manufacture and test the aspheric mirror.

Off-axis paraboloid is commonly used in optical systems and collimator, its greatest advantage is that no central shelter. Difficulties of manufacture depend on the processing precision of mirror, focal length, aperture size and off-axis. As an asymmetry surface, it is really a hard work to manufacture a surface with an amount of large off-axis, large-diameter, large volume of non-sphere. Here, some of the techniques such as "the way of cutting from master mirrors", "the way of filling up with sub mirrors", "the way of polishing sub mirrors directly", "the way of stretch deformations with stress" are discussed. Finally, some manufactures and results of master mirrors with diameter from 500 millimeters to 2000 millimeters are reported.

On the basis of three-order aberration theory, only adopt the method of null test using compensation of a compensating lens and a field lens to compensate ellipsoidal mirror with a scale of 1m and super large relative aperture, and succeed to design a compensator of the ellipsoidal mirror that the radius of curvature of vertex is 1555mm, aperture is 1000mm and e² is 0.9. Compared to compensator of ellipsoidal mirror with small aperture or small relative aperture, aperture of the compensating Lens is large and field lens is far from center of curvature of vertex of the ellipsoidal mirror, which destroys the conjugated relationship about field lens between compensating lens and the ellipsoidal mirror, and compensates aberration together with compensating lens. The result of design shows that the aberration is well corrected, and RMS below to λ/40 after fulfillment.