Results 111 to 120 of about 5,111 (331)
New techniques of multiple integral field spectroscopy [PDF]
, 2001 The work of this thesis is to investigate new techniques for Integral Field Spectroscopy (IPS) to make the most efficient use of modem large telescopes. Most of the work described is aimed at the FMOS for the SUBARU 8m telescope.
Ren, Deqing
core
Automatic Compressive Sensing of Shack–Hartmann Sensors Based on the Vision Transformer
PhotonicsShack–Hartmann wavefront sensors (SHWFSs) are crucial for detecting distortions in adaptive optics systems, but the accuracy of wavefront reconstruction is often hampered by low guide star brightness or strong atmospheric turbulence.
Qingyang Zhang +4 more
doaj +1 more source
Plaid‐Like Spin Splitting and Chirality of Magnon Bands in Antiferromagnetic MnTe2
Advanced Science, EarlyView.Helicity‐ and angle‐resolved Raman spectroscopy reveals chiral magnons in the non‐coplanar antiferromagnet MnTe 2. Combined with first‐principles calculations and spin‐wave theory, the results establish its altermagnetic character through circular Raman dichroism, reduced rotational symmetry, and a distinctive plaid‐like momentum‐space magnon spin ...
Dirk Wulferding +10 more
wiley +1 more source
Observing techniques for astronomical laser guide star adaptive optics [PDF]
, 1998 We discuss astronomical observing requirements and their implementation using sodium-layer laser guide star adaptive optics. Specific issues requiring implementation include the ability to place the astronomical object at different locations within the ...
Max, C. E. +4 more
core
Primary beam calibration for commensal telescopes utilizing offset optics
Frontiers in Astronomy and Space SciencesIntroductionAccurate primary beam calibration is essential for precise brightness measurements in radio astronomy. The VLA Low-band Ionosphere and Transient Experiment (VLITE) faces challenges in calibration due to the offset Cassegrain optics used in ...
Emil Polisensky +3 more
doaj +1 more source
Advanced Science, EarlyView.Complex microarchitectures emerge from simple flow‐driven transformations as static mixers iteratively reorient and split material domains. Coupled with diverse deposition strategies, chaotic printing provides an accessible platform for fabricating architected materials that support biologically and chemically relevant processes. ABSTRACT Nature builds
Edna Johana Bolívar‐Monsalve +7 more
wiley +1 more source
Astronomical Adaptive Optics using Multiple Laser Guide Stars [PDF]
, 2007 Over the past several years, experiments in adaptive optics involving multiple natural and laser guide stars have been carried out at the 1.55 m Kuiper telescope and the 6.5 m MMT telescope.
Baranec, Christoph James
core
On-sky Demonstration of Second-stage Wave-front Control with a Photonic Lantern
The Astronomical JournalGround-based direct imaging of exoplanets at high contrast requires precise correction of atmospheric turbulence using adaptive optics (AO). The planet-to-star contrast ratio at small angular separations from the host star is often limited by non-common ...
Aditya R. Sengupta +16 more
doaj +1 more source
Structural Colors from Modulated Topological Defects in Molecular Smectic Liquid Crystals
Advanced Science, EarlyView.Rather than using dyes and pigments, nature produces the colors of some butterflies and beetles through optical interference phenomena. This study describes an original biomimetic strategy exploiting the spontaneous formation of modulated linear defects in thin films of 8CB, a common molecular liquid crystal.
Camille N. Mahyaoui +7 more
wiley +1 more source
A Test Facility For Astronomical X-Ray Optics [PDF]
, 1989 Grazing incidence x-ray optics for x-ray astronomical applications are used outside the earths atmosphere. These devices require a large collection aperture and the imaging of an x-ray source which is essentially placed at infinity.
Christensen, Finn Erland +5 more
core +1 more source