With the continuous exploration of the universe and astronomy’s development, the telescopes are bigger and bigger. Horizon structure is widely used in the modern large telescopes rack, which carries dozens, even thousands of tons of the rotary parts and demands high accuracy and good stability. Therefore, it is one of the key technologies for large telescope to develop the precision support technology integrated direct drive with large load, high stiffness, low friction, even frictionless. Magnetic suspension bearing has not only the advantage of non-contact, no friction, high rigidity, high precision, low power, low mechanical assembly requirements, but also is integrated with the driven torque motor, which simplifies the structure, reduces the cost. This paper explores one kind of active bias magnetic suspension bearing integrated with direct drive technology based on multidisciplinary design optimization (MDO), which provides a new choice and view for the modern large astronomical telescope tracking system.
The site testing shows that Antarctic Dome A is one of the best site on earth for astronomical observations, for wavelength ranging from visible to infrared and sub-millimeter. Continuous observation for nearly four months in polar nights makes Dome A quite suitable for time domain astronomy. In the past decade CCAA already led a series of Antarctic astronomy activities and telescope projects which will be introduced in this paper. The first generation telescope is Chinese Small Telescope Array known as CSTAR, which was composed of four identical telescopes with 145mm entrance pupil, 20 square degrees FOV and different filters, all pointing to the celestial South Point, mainly used for variable stars detection and site testing. The telescope was deployed in Dome A in Jan. 2008, and followed by automatic observations for four consecutive winters. Three Antarctic Survey Telescopes (AST3) is the second generation telescope capable of pointing and tracking in very low temperature, with 500mm entrance pupil, 8.5 square degree FOV. AST3-1 and AST3-2 were respectively mounted on Dome A in Jan. 2012 and 2015, fully remotely controlled for supernovae survey and exoplanets searching. In Aug. 2017, AST3-2 successfully detected the optical counterpart of LIGO Source GW 170817. Now AST3-3 is under development for both optical and near infrared sky survey by matching different cameras. Based on the experience of the above smaller sized optical telescopes, the 2.5m Kunlun Dark Universe Survey Telescope (KDUST) was proposed for high resolution imaging over wide field of view. Currently the KDUST proposal was submitted to the government and waiting for project review.
China SONG telescope would achieve the goal for long time continuous, uninterrupted, full automatic observation and
works in the diffraction limit condition, what's more, it must realize 0.3 arc second tracking precision without guide star.
This paper describes the integration and fine-tuning of the China SONG Drive Systems. It discusses the different problems
encountered during the integration and commissioning. The servo model that was used to simulate the problems and to find
new solutions is described as well as test results and advanced analysis methods.
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.
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.
The modern large telescope is endowed with advanced imaging systems and active optics, resulting in very high
peak angular resolution. The drive systems for the telescope must consequently be able to guarantee a tracking accuracy
better than the telescope angular resolution, in spite of unbalanced and sudden loads such as wind gusts and in spite of a
structure that, because of its size, can not be infinitely stiff, which puts forward a great challenge to the telescope' drive
system. Modern telescope's drive system is complicated, which performance and reliability directly affect the telescope
tracking performance and reliability. Redundant technology is one of the effective ways to improve the security of the
system. This paper will introduce one redundant synchronous control method for direct drive torque motor of large
diameter telescope drive system, which can effectively improve the telescope drive system tracking precision and
improve the reliability, stability and anti-jamming ability.
The Stellar Oscillations Network Group (SONG) is an initiative which aims at designing and building a groundbased
network of 1m telescopes dedicated to the study of phenomena occurring in the time domain. Chinese
standard node of SONG is an Alt-Az Telescope of F/37 with 1m diameter. Optics derotator control system of
SONG telescope adopts the development model of "Industrial Computer + UMAC Motion Controller + Servo
Motor".1 Industrial computer is the core processing part of the motion control, motion control card(UMAC) is
in charge of the details on the motion control, Servo amplifier accepts the control commands from UMAC, and
drives the servo motor. The position feedback information comes from the encoder, to form a closed loop control
system. This paper describes in detail hardware design and software design for the optics derotator servo control
system. In terms of hardware design, the principle, structure, and control algorithm of servo system based on
optics derotator are analyzed and explored. In terms of software design, the paper proposes the architecture of
the system software based on Object-Oriented Programming.