The optical system of an adaptive 25-m telescope with a composite primary mirror composed of spherical segments

2007 ◽  
Vol 74 (2) ◽  
pp. 90 ◽  
Author(s):  
V. V. Sychev ◽  
V. B. Kasperskiĭ ◽  
M. L. Mashinina
Keyword(s):  
Optical System ◽  
Primary Mirror ◽  
Composite Primary Mirror

A Golay3 sparse aperture optical system of primary mirror with free-form surface

2021 ◽  
Vol 28 (1) ◽  
pp. 113-118
Author(s):  
Bin Chen ◽  
Quanying Wu ◽  
Junliu Fan
Keyword(s):  
Optical System ◽  
Free Form ◽  
Primary Mirror ◽  
Sparse Aperture ◽  
Free Form Surface

Application of Interferometry Measurement in Large-Scale Optic-Electrical Theodolite

2013 ◽  
Vol 303-306 ◽  
pp. 335-338
Author(s):  
Nan Zhao ◽  
Zhi Yuan Sun
Keyword(s):  
Optical System ◽  
Large Scale ◽  
Optical Design ◽  
High Accuracy ◽  
Practical Application ◽  
Important Method ◽  
Primary Mirror ◽  
Accuracy Measurement ◽  
Mechanical Structure ◽  
High Accuracy Measurement

Interferometry is a very important method in high accuracy measurement for optical system. This article briefly introduced the conception of interferometry and took a product of 4D Technology as an example to carry on the measurement. A large-scale optic-electrical Theodolite in assemblage was measured, and its primary mirror was 400mm in diameter. With the analysis of the results, some micro adjustments of the mechanical structure proceed, and it made the system perform better. The final results of the whole system is 1.061λ in P-V value and 0.1136λ in RMS value (λ=632.8nm), this meets the demand of optical design and practical application. The result demonstrates that interferometry is a good way to be utilized and optimize in the procedure of assemble.

Simultaneous null test of primary mirror and tertiary mirror in off-axis three-mirror optical system

2016 ◽  
Author(s):  
Yajun Niu ◽  
Jun Chang ◽  
Weilin Chen ◽  
Benlan Shen
Keyword(s):  
Optical System ◽  
Primary Mirror

Design progression of an all-composite primary mirror for the FIRST Telescope

2000 ◽  
Author(s):  
Steven J. Connell ◽  
Kelly J. Dodson ◽  
Zvi Friedman ◽  
Brian Cantanzaro ◽  
Shaun A. Whitmore ◽  
...  
Keyword(s):  
Primary Mirror ◽  
Composite Primary Mirror

scholarly journals The Large Sky Area Multi-Object Fibre Spectroscopy Telescope (Lamost)

1998 ◽  
Vol 11 (1) ◽  
pp. 493-493
Author(s):  
Yaoquan Chu
Keyword(s):  
Optical Fibre ◽  
Optical System ◽  
Field Of View ◽  
Plane Mirror ◽  
Schmidt Telescope ◽  
Active Optics ◽  
Primary Mirror ◽  
X Ray ◽  
The North ◽  
Angular Field Of View

Abstract In China, we will start to build a new spectroscopic survey telescope. It will be a meridian reflecting Schmidt telescope. The optical system is horizontal. The primary mirror is spherical and segmented. It faces towards the north. In its spherical center there is a plane mirror which is segmented too. The different shape of reflecting Schmidt plate is realized by active optics. The clear aperture is 4 m and f-ratio is 5. The angular field of view is 5 square degree, 4000 objects can be observed simultaneously by using optical fibre. The science goal is to make a 20000 square degrees spectroscopic survey, including ten million galaxies and stars, many variable objects and the identification of numerous objects found by radio, x-ray, IR and other survey in these sky areas.

A Field Emission System For Transmission Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 298-299
Author(s):  
Michel Troyonal ◽  
Huei Pei Kuoal ◽  
Benjamin M. Siegelal
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Optical System ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Objective Lens ◽  
Electron Optical System ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Emission System

A field emission system for our experimental ultra high vacuum electron microscope has been designed, constructed and tested. The electron optical system is based on the prototype whose performance has already been reported. A cross-sectional schematic illustrating the field emission source, preaccelerator lens and accelerator is given in Fig. 1. This field emission system is designed to be used with an electron microscope operated at 100-150kV in the conventional transmission mode. The electron optical system used to control the imaging of the field emission beam on the specimen consists of a weak condenser lens and the pre-field of a strong objective lens. The pre-accelerator lens is an einzel lens and is operated together with the accelerator in the constant angular magnification mode (CAM).

Information and estimation in image processing

1987 ◽  
Vol 45 ◽  
pp. 14-17
Author(s):  
B. Roy Frieden
Keyword(s):  
Image Processing ◽  
Optical System ◽  
Large Amplitude ◽  
Communication Theory ◽  
Image Data ◽  
Direct Approach ◽  
Ill Posed

Despite the skill and determination of electro-optical system designers, the images acquired using their best designs often suffer from blur and noise. The aim of an “image enhancer” such as myself is to improve these poor images, usually by digital means, such that they better resemble the true, “optical object,” input to the system. This problem is notoriously “ill-posed,” i.e. any direct approach at inversion of the image data suffers strongly from the presence of even a small amount of noise in the data. In fact, the fluctuations engendered in neighboring output values tend to be strongly negative-correlated, so that the output spatially oscillates up and down, with large amplitude, about the true object. What can be done about this situation? As we shall see, various concepts taken from statistical communication theory have proven to be of real use in attacking this problem. We offer below a brief summary of these concepts.

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