The Multi-channel Photometric Survey Telescope (Mephisto) is a wide-field ground based telescope with a 1.6m primary mirror and 2° field of view, proposed by Yunnan University. The telescope will be capable of imaging the northern sky in three colors simultaneously and deliver a colored movie of the universe. The R-C system with lens corrector was adopted as the optical system considering of the image quality requirement, light obscuration and camera arrangement, in which three cubic splitters were adopted for the three channel beams in order to get satisfied image quality over the whole field of view. Dichroic coating on the cubic will lead to nonuniform efficiency on the focal plane due to the polarization problem and wide incident angle, which need calibration. The image quality represented in 80% encircled light energy is around 0.6arcsec. In order to keep the optimal image quality in any operational conditions, a 5-DOF mechanism was designed to actively adjust M2 mirror positions according to the wavefront sensors or by direct star psf. Now the telescope are under developing in Nanjing, expected to be installed at Lijiang observatory before the end of 2021.
The study of supermassive black hole (SMBH) is one of the most confusing astronomical topics. However, little is known about the co-evolution of SMBH and galaxies, and also the formation process of SMBH. SMBH is considered to be a celestial body on the cosmic scale. As a probe, SMBH plays an irreplaceable key role in the study of the structure and evolution of the universe. The above-mentioned scientific researches requires 10 micro arcsecond astrometry precision. Based on the differential delay interferometry, we plan to develop a prototype long baseline optical interferometry facility to achieve high precision astrometry. The planned prototype facility includes three 500mm siderostats, and the detection waveband covers both near infrared and short wave infrared (J, H). The astrometry precision of the prototype facility is expected to be at the level of ten micro arcseconds.
The spherical primary mirror (Mb) of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is
segmented and composed of 37 hexagonal sub-mirrors, and segmented active optics method is successfully developed in
it. LAMOST project has passed through the project acceptance in 2009. The success of LAMOST makes deployable
primary mirror possible. The deployable large aperture space astronomical telescope is one of the most development
potential space observation spacecrafts in the future. This paper is targeted at the reflecting Schmidt telescope LAMOST,
which has a 6.67X6.05m primary mirror. The feasibility of the deployable structure of the large reflecting space
telescope's primary mirror has been mainly researched. The analysis of the design scheme for the deployable primary
mirror has been carried out, and according to the feature and the design of LAMOST, a subdivision type deployment
scheme has been given; The locating principle of the both side wings and the locking device after deployment has been
analyzed; In addition the problems in the process of deployment is also preliminary discussed. This paper is targeted at
the reflecting Schmidt telescope LAMOST, which has a 6.67X6.05 primary mirror. The feasibility of the deployable
structure of the large reflecting telescope's primary mirror has been mainly researched. The analysis of the design
scheme for the deployable primary mirror has been carried out, and according to the feature and the design of LAMOST,
a subdivision type deployment scheme has been given; The locating principle of the both side wings and the locking
device after deployment has been analyzed; In addition the problems in the process of deployment have been preliminary
LAMOST is a quasi-meridian reflecting Schmidt telescope, which consists of a reflecting Schmidt corrector MA, a
spherical primary mirror MB and a focal plane. The telescope with its optical axis tilted by an angle of 25° to the horizon
tracks the celestial objects by the movements of MA to make the light throughout aim at MB, and MB mirror consists of
37 spherical segments hanged upside down on the truss which tilted by about 25° to the horizon. This paper presents a
design of MB sub-mirror segment handling manipulator for LAMOST, carries out a simulation analysis, presents an
engineering program and describes the program's design principles and ideas. The manipulator including grab, declutch,
elevation, stretch, pitching, rotation, automatic control and several other parts, and the control system can coordinate all
these movements so that each segment can be located installed and handled precisely. In the structural design process the
stiffness and positioning accuracy problems have been taken full account of.
The reflecting Schmidt plate of the Large sky Area Multi-Object Spectroscopic Telescope (LAMOST) is composed of 24 hexagonal segments, each of which is 1100 mm from corner to corner and 25 mm in thickness. Both segmented mirror active optics and deformable mirror active optics are involved in the Schmidt plate so as to compensate for optical aberration and structural deformation. A prototype of the segment support system with dummy aluminum mirror had been setup and tested during 2003 to 2004, afterwards, based on the evaluation of test, the whole support system was updated to a backlash-free and light-weighted design. For the segmented mirror active optics, the segment mirror support system is to fulfill motions of tip, tilt and piston with three linear positioning actuators. Instead of self-alignment bearing adopted in the early prototype, a centering diaphragm is employed to realize a backlash-free pintle. And a lever with reduction of 10:1 is introduced to each of the three positioning actuator mechanisms, respectively, to obtain greater load capacity and further finer output displacement, as hence releases requirement and cost of the actuators. For better performance, high strength steel blades are used in tension state for pivots of the levers preloaded with longitudinal springs. To gap the mirror segments with respect to each other for making proper space for edge sensors, three adjustable fixtures are implemented for each segment mirror module to do translation and pistion on three conrresponding nodes on the top layer of the gross mirror cell truss before being anchored once and forever. In addition, safety measurements as well as anti-rotation mechanism have been taken into consideration throughout the design and development process. This paper describes the mechanical design and related analysis of the segment mirror support system in detail.