The Principles of Astronomical Telescope Design (Astrophysics and Space Science Library)

Jingquan Cheng

Language: English

Pages: 634

ISBN: 0387887903

Format: PDF / Kindle (mobi) / ePub


This book presents a complete summary of the author's twenty five years of experience in telescope design. It provides a general introduction to every aspect of telescope design. It also discusses the theory behind telescope design in depth, which makes it a good reference book for professionals. It covers Radio, Infrared, Optical, X-Ray and Gamma-Ray wavelengths. Originally published in Chinese.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In this situation, it is necessary to adjust the entrance width to W0 ¼ fc Dy, so that both sides of the images are cut out. The efficiency of the spectrograph is reduced. To satisfy the condition set by Equation (1. 29), a larger grating and collimator Fig. 1. 14. The image positions in the spectrum after diffraction. 1. 2 General Astronomical Requirements 23 are required; however, these are usually difficult. Therefore, two cases exist: (a) nongrating-limited case and (b) grating-limited case. In the grating limited case, the entrance width is reduced and the spectrograph efficiency decreases by a factor of e: e ¼ fc Dy=ðD Á Fc bÞ ¼ ðW=DÞðDv=bÞOg (1:30) where W and Og are grating parameters defined in Table 1.

1982) pointed out that the surface error of any thin mirror may be reduced by an increase of the mirror support points and, in theory, a mirror can have a very large aspect ratio. Traditional telescope mirrors had their aspect ratios smaller than 10. Newly designed monolithic mirror telescopes have their mirror aspect ratios much larger than 20 and newly built segmented mirror telescopes have aspect ratios as large as 110. In an extreme case, the thin adaptive secondary mirror has an aspect ratio of 320.

8. 2. 2 Backup Structure Design. . . . . . . . . . . . . . . . . . . . . . . . . 8. 2. 3 Design of Chopping Secondary Mirror . . . . . . . . . . . . . . 8. 2. 4 Sensors, Metrology, and Optical Pointing Telescopes . . 8. 2. 5 Active Optics Used in Millimeter Antennas . . . . . . . . . . 8. 2. 6 Antenna Lightning Protection . . . . . . . . . . . . . . . . . . . . 8. 3 Carbon Fiber Composite Materials . . . . . . . . . . . . . . . . . . . . . . 8. 3. 1 Properties of Carbon Fiber Composites . . . . . . . . . . . . . 8. 3. 2 Thermal Deformation of Shaped Sandwiched Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4. 1 Positioning Support Systems for Optical Mirrors Any rigid body has six degrees of freedom. Therefore, the best mirror support is the so-called ‘‘kinematic’’ mounting, which fixes just six rigid body degrees of 2. 3 Mirror Polishing and Mirror Supporting 127 freedom of a mirror. These six degrees of freedom can be applied on a single point, but stresses will be produced around it, or on three or more points. In some cases, the axial and radial positioning points are separately grouped, each with three support points.

99% 7. 29% 0. 17% Fig. 1. 4. An array of apertures in an interferometer and the resulting diffraction pattern. Using the same method, the diffraction patterns for an unfilled aperture field can be derived. Figure 1. 4 shows an array of apertures in an interferometer and its radiation pattern or its point spread function. It is the intensity diffraction pattern that determines the angular resolution of an optical telescope. The angular resolution is defined as the minimum angle between two distinguishable objects in image space.

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