The imaging quality and resolution of telescopes are deeply affected by the vibration that caused by electromechanical system and wind shake. Normally, vibration is caused by insufficient damping of the structure. In this paper, an active damper system based on linear motor is proposed to suppress vibration. The model of the whole control system is established at the beginning of this paper. LQR (Linear Quadratic Regulator) algorithm is proposed and the simulation is performed based on actual parameters of system. The results show that the system has a higher stability with higher Q value. The dynamic characteristics of the structure was obtained by analyzing the modal test data from accelerators. The experiments have been carried out to test the performance of the system. The results indicated that the active vibration damper can reduce the structure vibration 93.8% at 5.5Hz and increase the stiffness of structure.
SONG (Stellar Oscillation Network Group) is an international project to form a global observing network of eight 1- meter class telescopes. China joined this project and funded one node telescope for this network. By the end of 2013, the Chinese SONG telescope has been installed on the Delinha observing site of Purple Mountain Observatory in Qinghai province. This paper will give the introduction of this telescope, including its optical system, structure and control system. Besides, the preliminary observing performance of the telescope on site will be given in the second part of this paper.
SONG is an international initiative to design, build, and utilize a global network of eight 1-meter class
telescopes to be operated as a whole-Earth telescope. The telescope is composed of system of azimuth axis, rotating
table, fork, system of elevation axis, top-ring, up and down truss, system of primary mirror and so on. For an
astronomical telescope mount, having a high stiffness to support the mirror cell and instruments is its basic function.
Finite element method (FEM) is a powerful tool to help structure design engineer to achieve this goal. In this paper, with
the help of ANSYS, the static and modal analysis, calculation and optimization of the SONG telescope mount will be
given. The modal result which is used for avoiding resonance and fatigue failure of the telescope acquire natural
frequency of telescope. The FEM results show that the structure, designed for SONG telescope, is feasible and reliable
and have a high stiffness-to-weight ratio to meet the optical demands.
In recent years, Nanjing Institute of Astronomical Optics and Technology (NIAOT) has made several telescopes for
observatories all around the world. In 2011 NIAOT just finished the development of a 2.5m optical/infrared telescope
mount. First part of this paper is to introduce the mount structure and their adjustment work. Second part is to give an
introduction of the mount performance test methods and test results finished on NIAOT workshop.
KEYWORDS: Computer programming, Control systems, Telescopes, Servomechanisms, Mirrors, Amplifiers, Data transmission, Control systems design, Lithium, Astronomical imaging
The 2.5m optical/infrared telescope is an F/8 telescope comprising one Cassegrain foci, two Nasmyth foci and two
student Nasmyth foci. This paper presents a brief description of the physical structure, conceptual design, hardware
implementing measure and software structure in the positioning control system of M2&M3. The graphical user interface
application (Qt) is adopted to design the software. During the full working range the M2 focus and decenter achieve the
positioning repeatability is better than ±4μm and the M2 tilt is better than 10 μrad. The M3 angular positioning and
locking accuracy is better than 10 arcsec and repeatability is better than 2 arcsec RMS.
SONG is initiated by Danish to design, build, and utilize a global network of eight 1-meter class telescopes to be
operated as a whole-Earth telescope. China has joined the international SONG project in 2009 and will build one 1-meter
telescope as the node of SONG global network in China. Now the telescope is during the period of building. This paper
will give an introduction of Chinese SONG telescope, including telescope requirements, telescope design and other
information.
KEYWORDS: Telescopes, Mirrors, Control systems, Computer programming, Astronomical imaging, Optical instrument design, Control systems design, Astronomy, Astronomical telescopes, Information technology
Telescope is a very important tool for astronomers to survey and study the stellar stars and astronomical phenomena. The
performance of a telescope is its capability to track the observing objects and keep the image on the field of view during
the observing period. All these functions will be achieved by telescope mount, including mount control system. The
mount is to support the mirror cell and keep the mirror cell position stability. Meanwhile, with the help of control
system, the mount acts as tracker of the observing objects. So, for a telescope, the mount and its control system play an
important role during the telescope operation. This paper gives an introduction of a mount structure designed for a 2.5m
optical/infrared telescope and the corresponding control system. Some of preliminary test results are also given in this
paper.
For an astronomical telescope mount, having a high stiffness to support the mirror cell and instruments is its basic
function. Traditionally, the mount is composed of azimuth base, azimuth axis, fork, altitude axis, tube, top-ring, etc. On
the other hand, telescope will be driven to track the observing objects during operation. So, for the mechanical structure
design engineer, finding a high stiffness-to-weight ratio mount is the main task. Finite element method (FEM) is a
powerful tool to help structure design engineer to achieve this goal. ANSYS is one of these kinds of finite element
method software. In this paper, with the help of ANSYS, the static and dynamic analysis, calculation and optimization of
a 2.5m telescope mount will be given. The FEM results show that the structure, designed for 2.5m telescope, is feasible
and reliable and have a high stiffness-to-weight ratio to meet the optical demands.
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