Results 31 to 40 of about 669,031 (383)

Final Results from the Hubble Space Telescope Key Project to Measure the Hubble Constant [PDF]

open access: yes, 1998
We present here the final results of the Hubble Space Telescope (HST) Key Project to measure the Hubble constant. We summarize our method, the results, and the uncertainties, tabulate our revised distances, and give the implications of these results for ...
W. Freedman   +14 more
semanticscholar   +1 more source

Highly Reflective Silver-Enhanced Coating with High Adhesion and Sulfurization Resistance for Telescopes

open access: yesNanomaterials, 2022
Highly reflective metal coatings are essential for manufacturing reflecting telescope mirrors to achieve the highest reflectivity with broad spectral bandwidth.
Hsing-Yu Wu   +6 more
doaj   +1 more source

First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole [PDF]

open access: yesAstrophysical Journal, 2019
We present measurements of the properties of the central radio source in M87 using Event Horizon Telescope data obtained during the 2017 campaign. We develop and fit geometric crescent models (asymmetric rings with interior brightness depressions) using ...
K. Akiyama   +213 more
semanticscholar   +1 more source

The eROSITA X-ray telescope on SRG [PDF]

open access: yesAstronomy & Astrophysics, 2020
eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the primary instrument on the Spectrum-Roentgen-Gamma (SRG) mission, which was successfully launched on July 13, 2019, from the Baikonour cosmodrome.
P. Predehl   +92 more
semanticscholar   +1 more source

THE LARGE AREA TELESCOPE ON THE FERMI GAMMA-RAY SPACE TELESCOPE MISSION [PDF]

open access: yes, 2009
The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view (FoV), high-energy γ-ray telescope, covering the energy range from below 20 MeV to more ...
W. Atwood   +239 more
semanticscholar   +1 more source

Umpolung Synthesis of Pyridyl Ethers by BiV‐Mediated O‐Arylation of Pyridones

open access: yesAngewandte Chemie, Volume 134, Issue 51, December 19, 2022., 2022
We demonstrate that sterically‐ and electronically‐diverse pyridyl ethers can be accessed via BiV‐mediated C−O coupling of 2‐ or 4‐pyridones with arylboronic acids. Use of a bismacyclic reagent not only confers modularity on our methodology, but also results in highly regioselective O‐arylation that is unprecedented for BiV.
Katie Ruffell   +4 more
wiley   +2 more sources

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

Fermi Large Area Telescope Fourth Source Catalog [PDF]

open access: yesAstrophysical Journal Supplement Series, 2019
We present the fourth Fermi Large Area Telescope catalog (4FGL) of γ-ray sources. Based on the first eight years of science data from the Fermi Gamma-ray Space Telescope mission in the energy range from 50 MeV to 1 TeV, it is the deepest yet in this ...
S. Abdollahi   +167 more
semanticscholar   +1 more source

Wishing for the Watch Face in Jonathan Swift’s “The Progress of Beauty”

open access: yesABO : Interactive Journal for Women in the Arts 1640-1830, 2018
This article illuminates the technological underpinnings of Jonathan Swift’s satire, “The Progress of Beauty” (1719), by exploring how eighteenth-century poetics of beauty and scientific progress pit human against automaton.
Jantina Ellens
doaj   +1 more source

Receiving vectors of muon telescope of cosmic ray station Novosibirsk

open access: yesSolar-Terrestrial Physics, 2016
The method of receiving vectors allows us to determine cosmic ray anisotropy at every moment of time. Also, the method makes it possible to study fast anisotropy fluctuations related to the interplanetary medium dynamics.
Yanchukovsky V.L.   +4 more
doaj   +1 more source

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