A simple, dual knife-edge test for phasing segmented aperture space telescopes

2018 ◽  
Author(s):  
James K. Wallace ◽  
Frank Loya ◽  
Shannon Kian Zareh ◽  
David Redding
Keyword(s):  
Knife Edge ◽  
Space Telescopes

scholarly journals FOUCAULT KNIFE-EDGE METHOD APPLICATION FOR ADAPTATION OF THE MILLIMETRON OBSERVATORY MIRROR SYSTEM

2020 ◽  
Vol 8 (1) ◽  
pp. 27-34
Author(s):  
Peter S. Zavyalov ◽  
Maxim S. Kravchenko ◽  
Elena S. Zhimuleva
Keyword(s):  
Software Package ◽  
Degrees Of Freedom ◽  
Mirror System ◽  
Optical Scheme ◽  
Knife Edge ◽  
Space Telescopes ◽  
Main Mirror ◽  
Edge Method ◽  
6 Degrees Of Freedom

In the process of space telescopes development there is an increase in the diameter of their reflector.In this case, composite reflectors are used more often. So the main mirror of the Millimetron observatory consists of 96 elements, each of which can deviate from the calculated position during the transition to the transport position and back to the working position when the telescope is put into orbit. In this paper, we consider the possibility of using Foucault knife-edgemethod to solve the problem of adapting the mirror system of the Millimetron observatory. An optical scheme for solving the adaptation problem is proposed. It was simulated in the Zemax software package. In the process of modeling, the effects arising from the deviation of all the components of the reflector in 6 degrees of freedom were studied. The advantage in the approach to the digital matrix in the telescope is highlighted.

scholarly journals Stray light characterization with ultrafast time-of-flight imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
L. Clermont ◽  
W. Uhring ◽  
M. Georges
Keyword(s):  
Path Length ◽  
Imaging System ◽  
Time Of Flight ◽  
Optical Path Length ◽  
Optical Path ◽  
Stray Light ◽  
Laser Source ◽  
Space Telescopes ◽  
Characterization Methods ◽  
Instance Space

AbstractUnderstanding stray light (SL) is a crucial aspect in the development of high-end optical instruments, for instance space telescopes. As it drives image quality, SL must be controlled by design and characterized experimentally. However, conventional SL characterization methods are limited as they do not provide information on its origins. The problem is complex due to the diversity of light interaction processes with surfaces, creating various SL contributors. Therefore, when SL level is higher than expected, it can be difficult to determine how to improve the system. We demonstrate a new approach, ultrafast time-of-flight SL characterization, where a pulsed laser source and a streak camera are used to record individually SL contributors which travel with a specific optical path length. Furthermore, the optical path length offers a means of identification to determine its origin. We demonstrate this method in an imaging system, measuring and identifying individual ghosts and scattering components. We then show how it can be used to reverse-engineer the instrument SL origins.

scholarly journals Extinction-free Census of AGNs in the AKARI/IRC North Ecliptic Pole Field from 23-band infrared photometry from Space Telescopes

2020 ◽  
Vol 499 (3) ◽  
pp. 4068-4081 ◽  
Author(s):  
Ting-Wen Wang ◽  
Tomotsugu Goto ◽  
Seong Jin Kim ◽  
Tetsuya Hashimoto ◽  
Denis Burgarella ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
Cosmic Time ◽  
Spectral Energy ◽  
Wide Field ◽  
Space Telescopes ◽  
Distribution Modelling ◽  
Star Forming ◽  
The North ◽  
Band Filter ◽  
Infrared Survey

ABSTRACT In order to understand the interaction between the central black hole and the whole galaxy or their co-evolution history along with cosmic time, a complete census of active galactic nucleus (AGN) is crucial. However, AGNs are often missed in optical, UV, and soft X-ray observations since they could be obscured by gas and dust. A mid-infrared (MIR) survey supported by multiwavelength data is one of the best ways to find obscured AGN activities because it suffers less from extinction. Previous large IR photometric surveys, e.g. Wide field Infrared Survey Explorer and Spitzer, have gaps between the MIR filters. Therefore, star-forming galaxy-AGN diagnostics in the MIR were limited. The AKARI satellite has a unique continuous nine-band filter coverage in the near to MIR wavelengths. In this work, we take advantage of the state-of-the-art spectral energy distribution modelling software, cigale, to find AGNs in MIR. We found 126 AGNs in the North Ecliptic Pole-Wide field with this method. We also investigate the energy released from the AGN as a fraction of the total IR luminosity of a galaxy. We found that the AGN contribution is larger at higher redshifts for a given IR luminosity. With the upcoming deep IR surveys, e.g. JWST, we expect to find more AGNs with our method.

scholarly journals Partial aperture imaging system based on sparse point spread holograms and nonlinear cross-correlations

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Angika Bulbul ◽  
Joseph Rosen
Keyword(s):  
Structural Changes ◽  
Imaging System ◽  
Current System ◽  
Three Dimensional ◽  
Phase Mask ◽  
Coded Aperture ◽  
Space Telescopes ◽  
Reconstruction Process ◽  
Cross Correlations ◽  
Equivalent Systems

AbstractPartial aperture imaging system (PAIS) is a recently developed concept in which the traditional disc-shaped aperture is replaced by an aperture with a much smaller area and yet its imaging capabilities are comparable to the full aperture systems. Recently PAIS was demonstrated as an indirect incoherent digital three-dimensional imaging technique. Later it was successfully implemented in the study of the synthetic marginal aperture with revolving telescopes (SMART) to provide superresolution with subaperture area that was less than one percent of the area of the full synthetic disc-shaped aperture. In the study of SMART, the concept of PAIS was tested by placing eight coded phase reflectors along the boundary of the full synthetic aperture. In the current study, various improvements of PAIS are tested and its performance is compared with the other equivalent systems. Among the structural changes, we test ring-shaped eight coded phase subapertures with the same area as of the previous circular subapertures, distributed along the boundary of the full disc-shaped aperture. Another change in the current system is the use of coded phase mask with a point response of a sparse dot pattern. The third change is in the reconstruction process in which a nonlinear correlation with optimal parameters is implemented. With the improved image quality, the modified-PAIS can save weight and cost of imaging devices in general and of space telescopes in particular. Experimental results with reflective objects show that the concept of coded aperture extends the limits of classical imaging.

scholarly journals On a knife edge: A preliminary investigation of clothing damage using rounded-tip knives

2020 ◽  
Vol 60 (6) ◽  
pp. 495-503
Author(s):  
Leisa Nichols-Drew ◽  
Rachel Armitage ◽  
Robert Hillman ◽  
Kelly J. Sheridan ◽  
Kevin J. Farrugia
Keyword(s):  
Preliminary Investigation ◽  
Knife Edge
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