Testing, characterization, and control of a multi-axis, high precision drive system for the Hobby-Eberly Telescope Wide Field Upgrade

2012 ◽  
Author(s):  
Ian M. Soukup ◽  
Joseph H. Beno ◽  
Gary J. Hill ◽  
John M. Good ◽  
Charles E. Penney ◽  
...  
2020 ◽  
Vol 13 (6) ◽  
pp. 1-9
Author(s):  
XU Hong-gang ◽  
◽  
HAN Bing ◽  
LI Man-li ◽  
MA Hong-tao ◽  
...  

2021 ◽  
Author(s):  
Fabio Falconi ◽  
Claudio Porzi ◽  
Filippo Scotti ◽  
Giovanni Serafino ◽  
Antonio Malacarne ◽  
...  

Abstract In the last decade, the interest in software-defined ultra-wideband (UWB) and tunable radio frequency (RF) apparatuses with low size, weight, and power consumption (SWaP), has grown dramatically, pushed by the new 6G vision where, RF equipment shall enable a large number of fundamental applications as UWB communications, robot localization mapping and control and high precision radars, all of them contributing in revolutionizing our life style. Unfortunately, the coexistence of ultra-wideband and software-defined operation, tunability and low SWaP represents a big issue in the current RF technologies. In this article, to the best of our knowledge, the first example of a complete tunable software-defined RF transmitter with low footprint (i.e. on photonic chip) is presented exceeding the state-of-the-art for the extremely large tunability range of 0.5-50 GHz without any parallelization of narrower-band components and with fast tuning (<200micros). This first implementation, represents a breakthrough in microwave photonics.


2014 ◽  
Vol 11 (S308) ◽  
pp. 437-442 ◽  
Author(s):  
S. Codis ◽  
Y. Dubois ◽  
C. Pichon ◽  
J. Devriendt ◽  
A. Slyz

AbstractIntrinsic alignments are believed to be a major source of systematics for future generation of weak gravitational lensing surveys like Euclid or LSST. Direct measurements of the alignment of the projected light distribution of galaxies in wide field imaging data seem to agree on a contamination at a level of a few per cent of the shear correlation functions, although the amplitude of the effect depends on the population of galaxies considered. Given this dependency, it is difficult to use dark matter-only simulations as the sole resource to predict and control intrinsic alignments. We report here estimates on the level of intrinsic alignment in the cosmological hydrodynamical simulation Horizon-AGN that could be a major source of systematic errors in weak gravitational lensing measurements. In particular, assuming that the spin of galaxies is a good proxy for their ellipticity, we show how those spins are spatially correlated and how they couple to the tidal field in which they are embedded. We will also present theoretical calculations that illustrate and qualitatively explain the observed signals.


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