Astronomical Telescope Design

Astronomical Telescope Design

Course Code: 031M4015H

Course Name: Astronomical Telescope Design

Credits: 3.0

Level: Undergraduate

Pre-requisites: General Astronomy, Optical Engineering, Mechanical Design, Finite Element Analysis, Precision Transmission Technology

Lecture Time: 9 weeks, 2 sessions/week, 3 hours/session, 54 hours

Instructors: Zhang Haiying, Hu Qiqian, Wang Guomin

Course Description

Astronomical telescopes are important devices that astronomers use to observe stars and explore the mysteries of the universe. The performance of astronomical telescopes directly affects the level of astronomy research. Therefore, how to design an astronomical telescope with excellent performance is very important for astronomy research. This course consists of three parts: basic knowledge of astronomical telescopes, optical telescopes and solar telescopes. The basic knowledge section systematically introduced the development history of telescopes and astronomy, the celestial coordinate system and its transformation, the rack form of the telescope, the wave optics and geometric optics foundation, the engineering structural mechanics and the finite element principle; the optical telescope section will introduce the basics of optical telescope design. Mirror support for telescopes, racks and tubes for telescopes, shafting and transmission of telescopes, and pointing and tracking technologies for telescopes; solar telescopes section will introduce solar physics basics and solar observation site selection and instruments, various types of solar telescopes, solar spectrum, monochromatic light, solar field velocity field observation equipment, and space solar observation equipment and solar radio telescope.

Topics and Schedule

Part Ⅰ Basic knowledge of astronomical telescope （18 hours）

1.Telescope and Astronomy (3 hours)
1.Importance of astronomy, the relationship between astronomy and astronomical instruments, the category of astronomical instruments.
2.The astrometry and instruments in ancient time
3.The classic methods of astrometry, nonuniformity of the earth movement, time and latitude measuring instruments, modern measurement for celestial body
4.The high accurate astrometry by radio telescope interferometer
5.Invention of telescope, earlier refractive telescopes
6.Invention of reflective telescopes
7.Development in science and technology in modern time improved development in telescope technology
8.Classic large telescopes before the 1990s
9.8-10 m modern telescopes with new technology
10.Giant ground-based telescopes in manufacturing, space telescopes
1. 2.Celestial coordinate system and its tranformation (2 hours)
1.Alt-azimuth coordinate system, equatorial coordinate system and horizontal coordinate system
2.Formulas transformation for celestial coordinate systems
1. 3.The Telescope Mountings (2 hours)
1.Function and constitute of the telescope mountings
2.Types and characteristic of the telescope mountings
3.Special telescope mountings, the heliostat and the coelostat
4.The image-field rotation of telescopes
1. 4.Basic knowledge on wave optics (5 hours)
1.Research objects in wave optics, the relevant mathematics formula, Concept about the space frequency and complex amplify, wave optics applications in telescope design
2.Theory of diffraction, Fresnel diffraction and Fraunhofer diffraction, imaging principle of telescopes
3.Point Spread Function, PSF for the typical pupil functions
4.Object-image Formulas based on the space frequency theory
5.Wave optics applications in the astronomy observation, theoretical resolving power of telescopes, focal depth, Criterion of perfect optics systems, evaluate of image quality of optics systems
6.Principle of astronomical interference, double pupil interference of mono-mirror, modern stellar interferometers
1. 5.Basic knowledge on the geometry optics (3 hours)
1.Basic theory of the geometry optics, the refraction law and the reflection law
2.Field of view and aperture, entrance pupil and exit pupil, Stop and vignetting, control for the principal rays
3.Formulas of close-axis spherical system, object-image formulas, amplification
4.Thin lenses and reflection spherical mirrors
5.Ideal optic systems, focal length and principal plane, main formulas
6.Typical optics of astronomy telescopes, refraction system and reflection system
1. 6.Engineering Structural Mechanics and the Principle about Finite Element (3 hours)
1.The application of engineering structural mechanics in astronomical telescope design
2.The formulas of material mechanics：strength, shear，torque，bending
3.The basic knowledge and formulas of elastic mechanics
4.The basic knowledge of finite element, finite element method for rods and plane stress
5.The relationship between structural deformation and telescope imaging
6.Some mechanical problems in part design

Part Ⅱ Optical telescope (18 hours)

7.General introduction of optical telescope (3 hours)
1.Introduction on optical telescope
2.Design and development process of optical telescope
3.Site and dome
4.Telescope installation on site and performance testing
1. 8.Mirror support technology (3 hours)
1.Primary mirror support
2.Secondary mirror support
3.Third mirror support
4.Small mirrors and Lens mount
5.Alignment between mirrors and adjust method
6.Methods to test the support performance
1. 9.Telescope mount and tube design (3 hours)
1.Equatorial mount
2.Altitude-azimuth mount
3.Altitude-altitude mount
4.Other special mounts
5.Tube design (mirror cell, center section, truss, etc.)
1. 10.Telescope shaft design and support bearing (3 hours)
1.Telescope shaft design
2.Structural mechanics calculation and analysis
3.Shaft support bearing
4.Methods to adjust and test the bearing performance
1. 11.Telescope drive technology (3 hours)
1.Worm gear drive
2.Gear drive
3.Friction drive
4.Direct drive
1. 12.Telescope pointing and tracking (3 hours)
1.Pointing error source and error analysis
2.Pointing model set up
3.Control device (motor, encoder, amplifier, etc.)
4.Telescope tracking control

Part Ⅲ Solar telescope (18 hours)

13.Solar observation and site selection (2 hours)
1.The significance of solar study
2.Solar physics fundamentals
3.The effect of Earth's atmosphere on solar observations
4.Solar observation site selection and instrumentation
1. 14.Imaging system of solar telescope (4 hours)
1.Chromosphere telescope
2.Coelostat and Heliostats
3.Sunseeker
4.Coronagraph
5.Multi-channel Solar Telescope
6.New Vacuum Solar Telescope
7.Pre-study on Chinese Giant Solar Telescope
1. 15.Instruments for solar spectrum observation (3 hours)
1.Characteristics of the solar spectrum
2.Grating spectrometer
3.Solar monochromator
4.Two-dimensional spectrometer
5.Fourier Transform Spectrometer
6.Integral Field Unit Spectrometer
1. 16.Solar monochromatic light observation instrument (3 hours)
1.Monochromatic light observation
2.Solar monochromator
3.Birefringent filter
4.Interference filter
5.Solid Michelson Interferometer
6.Multi-channel filter
1. 17.Measurement of solar magnetic field and velocity field (4 hours)
1.The significance of solar magnetic field measurement
2.The development of solar magnetic field measurement
3.The principle of solar magnetic field measurement
4.The observation equipment for solar velocity field
1. 18.Space Solar Observations and Solar Radio Observations (2 hours)
1.Development history of space solar observations
2.Balloon-borne solar telescope
3.The program of space solar observation
4.The significance of solar radio observations
5.Chinese Spectral Radioheliograph

Grading

The grades include check-in times, final examination and assignments of weekly homework

References

[1] Pierre Y. Bely, The Design and Construction of Large Optical Telescopes, New York: Springer, 2003

[2] Hu Qiqian, Yao Zhengqiu, Astronomical Telescope Design, China Science & Technology Press, 2013 (Chinese version)

[3] Hu Qiqian, Telescope technology and astronomical surveying, Southeast University Press, 2014 (Chinese version)

[4] Cheng Jingquan, Principles of astronomical telescope design, China Science & Technology Press, 2003 (Chinese version)

[5] Lin Yuanzhang, Introduction to solar physics, Science Press, 2000 (Chinese version)

[6] Huang Youran, et al. Observational astrophysics, Science Press, 1987 (Chinese version)