Results 51 to 60 of about 681,192 (361)

Modified Method to Detect the Turbulent Layers in the Atmospheric Boundary Layer for the Large Solar Vacuum Telescope

open access: yesAtmosphere, 2021
A method to detect the atmospheric turbulent layers using a single Shack–Hartmann wavefront sensor is discussed. In order to determine the height distribution of the atmospheric turbulence above a telescope, we register the wavefront distortions at ...
Artem Yurievich Shikhovtsev   +6 more
doaj   +1 more source

Comparative analysis of three mode-selection methods for solid-state lasers [PDF]

open access: yesE3S Web of Conferences, 2021
In the Nd3+:YAG pulsed Q-switched laser system, the selective output of several low order modes of TEM00, TEM01 and TEM11 is realized by adding a iris diaphragm, a telescope or a Gaussian mirror at an appropriate position in the resonator, and the three ...
Sun Yan
doaj   +1 more source

Wavelength-Dependent Seeing Systematically Changes the Normalized Slope of Telescopic Reflectance Spectra of Mercury

open access: yesRemote Sensing, 2022
Telescopic observations of Mercury consistently report systematic variations of the normalized spectral slope of visible-to-near-infrared reflectance spectra.
Kay Wohlfarth, Christian Wöhler
doaj   +1 more source

Building a CCD Spectrograph for Educational or Amateur Astronomy [PDF]

open access: yes, 2002
We discuss the design of an inexpensive, high-throughput CCD spectrograph for a small telescope. By using optical fibers to carry the light from the telescope focus to a table-top spectrograph, one can minimize the weight carried by the telescope and ...
Charles B. Hughes   +4 more
core   +1 more source

Science case for the Einstein telescope [PDF]

open access: yesJournal of Cosmology and Astroparticle Physics, 2019
The Einstein Telescope (ET), a proposed European ground-based gravitational-wave detector of third-generation, is an evolution of second-generation detectors such as Advanced LIGO, Advanced Virgo, and KAGRA which could be operating in the mid 2030s.
M. Maggiore   +17 more
semanticscholar   +1 more source

Freeform Wide Field-of-View Spaceborne Imaging Telescope: From Design to Demonstrator

open access: yesSensors, 2022
Wide field-of-view imaging optics offer a huge potential for space-based Earth observation enabling the capture of global data. Reflective imaging telescopes are often favored, as they do not show chromatic aberrations and are less susceptible to ...
Luca Schifano   +7 more
doaj   +1 more source

Hexapod Design For All-Sky Sidereal Tracking [PDF]

open access: yes, 2016
In this paper we describe a hexapod-based telescope mount system intended to provide sidereal tracking for the Fly's Eye Camera project -- an upcoming moderate, 21"/pixel resolution all-sky survey. By exploiting such a kind of meter-sized telescope mount,
Csépány, Gergely   +6 more
core   +2 more sources

Black holes with scalar hair in light of the Event Horizon Telescope [PDF]

open access: yesJournal of Cosmology and Astroparticle Physics, 2020
Searching for violations of the no-hair theorem (NHT) is a powerful way to test gravity, and more generally fundamental physics, particularly with regards to the existence of additional scalar fields.
Mohsen Khodadi   +3 more
semanticscholar   +1 more source

Low Vision Aids: Visual Outcomes and Barriers in Children with Low Vision

open access: yesDelhi Journal of Ophthalmology, 2019
Aims: To study the demographic profile, cause of low vision, visual outcome and the barriers in using low vision aids (LVA). Design: Prospective observational clinical study.
V. R. Venkataramanan   +5 more
doaj   +1 more source

Active optics: deformable mirrors with a minimum number of actuators [PDF]

open access: yesJournal of the European Optical Society-Rapid Publications, 2012
We present two concepts of deformable mirror to compensate for first order optical aberrations. Deformation systems are designed using both elasticity theory and Finite Element Analysis in order to minimize the number of actuators.
Laslandes M., Hugot E., Ferrari M.
doaj   +1 more source

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