Focal plane considerations for fiber laser wide field processing

Author(s):  
Mark Brodsky ◽  
Jack Gabzdyl
Keyword(s):  
Author(s):  
Ugur Yekta Basak ◽  
Seyedmahdi M. K. Kazempourradi ◽  
Erdem Ulusoy ◽  
Hakan Urey

2017 ◽  
Vol 13 (S334) ◽  
pp. 242-247
Author(s):  
Luca Pasquini ◽  
B. Delabre ◽  
R. S. Ellis ◽  
J. Marrero ◽  
L. Cavaller ◽  
...  

AbstractWe present the concept of a novel facility dedicated to massively-multiplexed spectroscopy. The telescope has a very wide field Cassegrain focus optimised for fibre feeding. With a Field of View (FoV) of 2.5 degrees diameter and a 11.4m pupil, it will be the largest etendue telescope. The large focal plane can easily host up to 16.000 fibres. In addition, a gravity invariant focus for the central 10 arc-minutes is available to host a giant integral field unit (IFU). The 3 lenses corrector includes an ADC, and has good performance in the 360-1300 nm wavelength range. The top level science requirements were developed by a dedicated ESO working group, and one of the primary cases is high resolution spectroscopy of GAIA stars and, in general, how our Galaxy formed and evolves. The facility will therefore be equipped with both, high and low resolution spectrographs. We stress the importance of developing the telescope and instrument designs simultaneously. The most relevant R&D aspect is also briefly discussed.


1995 ◽  
Vol 167 ◽  
pp. 213-220
Author(s):  
J. C. Cuillandre ◽  
Y. Melliers ◽  
R. Murowinski ◽  
D. Crampton ◽  
G. Luppino ◽  
...  

MOCAM is a wide field CCD camera, currently nearing completion, which will be offered to the Canada-France-Hawaii Telescope (CFHT) user community in 1995. The project is a collaboration between the CFHT, the Dominion Astronomical Observatory (DAO, Canada), the Institut des Sciences de l'Univers (INSU, France), Laboratoire d'Astrophysique de Toulouse (LAT, France) and the University of Hawaii (UH). In the interests of producing a reliable and effective camera in the shortest time, it was decided to use existing technologies rather than innovative ones. Two-edge buttable 2048 × 2048 15 μm pixel CCDs were obtained from the LORAL aerospace foundry, based on a mask designed by J. Geary at Smithsonian Astrophysical Observatory (SAO). They are mounted in a dewar designed by G. Luppino (UH); the focal plane mounting keeps the mosaic flat to within two pixels and the CCDs are aligned to within two pixels. A mechanical interface designed and fabricated by the DAO holds a 150 mm shutter and a filter wheel which has a positioning repeatability better than five μm.The four CCDs are operated in parallel by a San Diego GenIII controller adapted by LAT. The mosaic is read out in seven minutes and a single 33 Mb FITS file is generated to enable convenient on-line preprocessing. The user will control the system through a single CFHT Pegasus environment session. The camera field is 14′ × 14′ with a 0.″2 pixel sampling and the readout noise is less than seven electrons. The scientific goals of the initiators of the project are studies of distant clusters, deep galaxy counts and quasars surveys.


1987 ◽  
Author(s):  
J . A. Nousek ◽  
G. P. Garmire ◽  
G. R. Ricker ◽  
M. w. Bautz ◽  
A. M. Levine ◽  
...  

2012 ◽  
Vol 51 (22) ◽  
pp. 5419 ◽  
Author(s):  
Delphine Dumas ◽  
Manuel Fendler ◽  
Nicolas Baier ◽  
Jérôme Primot ◽  
Etienne le Coarer

2021 ◽  
Vol 9 ◽  
Author(s):  
Yumin Wu ◽  
Linpeng Lu ◽  
Jialin Zhang ◽  
Zhuoshi Li ◽  
Chao Zuo

In recent years, lensfree on-chip microscopy has developed into a promising and powerful computational optical microscopy technique that allows for wide-field, high-throughput microscopic imaging without using any lenses. However, due to the limited pixel size of the state-of-the-art image sensors, lens-free on-chip microscopy generally suffers from low imaging resolution, which is far from enough to meet the current demand for high-resolution microscopy. Many pixel super-resolution techniques have been developed to solve or at least partially solve this problem by acquiring a series of low-resolution holograms with multiple lateral sub-pixel shifting or axial distances. However, the prerequisite of these pixel super-resolution techniques is that the propagation distance of each low-resolution hologram can be obtained precisely, which faces two major challenges. On the one hand, the captured hologram is inherent pixelated and of low resolution, making it difficult to determine the focal plane by evaluating the image sharpness accurately. On the other hand, the twin-image is superimposed on the backpropagated raw hologram, further exacerbating the difficulties in accurate focal plane determination. In this study, we proposed a high-precision autofocusing algorithm for multi-height pixel-super-resolved lensfree on-chip microscopy. Our approach consists of two major steps: individual preliminary estimation and global precise estimation. First, an improved critical function that combines differential critical function and frequency domain critical function is proposed to obtain the preliminary focus distances of different holograms. Then, the precise focus distances can be determined by further evaluating the global offset of the averaged, low-noise reconstruction from all backpropagated holograms with preliminary focus distances. Simulations and experimental results verified the validity and effectiveness of the proposed algorithm.


2012 ◽  
Vol 20 (9) ◽  
pp. 1939-1944
Author(s):  
刘磊 LIU Lei ◽  
曹国华 CAO Guo-hua
Keyword(s):  

2016 ◽  
Author(s):  
Y. Komiyama ◽  
H. Nakaya ◽  
N. Kashikawa ◽  
T. Uchida

2017 ◽  
Author(s):  
Yizhi Liang ◽  
Long Jin ◽  
Jun Ma ◽  
Xue Bai ◽  
Bai-Ou Guan

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