Results 81 to 90 of about 33,599 (258)
Nature in Seclusion. The Monastic Republic of Letters in Southern Germany**
Abstract Monasteries were famous for their extensive libraries and richly decorated churches. Less well known are their observatories and their mathematical‐physical collections with telescopes, air pumps, and friction machines. But how did the way of life in the monastery and scientific practices influence each other?
Julia Bloemer
wiley +1 more source
Astrometry with the Keck-Interferometer: the ASTRA project and its science
The sensitivity and astrometry upgrade ASTRA of the Keck Interferometer is introduced. After a brief overview of the underlying interferometric principles, the technology and concepts of the upgrade are presented.
Andrea M. Ghez+44 more
core +1 more source
Method for estimating the accuracy of astrometric (rectangular coordinates) and photometric (diameters and magnitudes) characteristics of commercial scanners is proposed and applied.
Yu. I. Protsyuk+10 more
doaj +1 more source
Abstract This paper conducts a multi‐instrument and data assimilation analysis of the three‐dimensional ionospheric electron density responses to the total solar eclipse on 08 April 2024. The altitude‐resolved electron density variations over the continental US and adjacent regions are analyzed using the Millstone Hill incoherent scatter radar data ...
Ercha Aa+7 more
wiley +1 more source
Magnetic Field Studies in BL Lacertae through Faraday Rotation and a Novel Astrometric Technique
It is thought that dynamically important helical magnetic fields twisted by the differential rotation of the black hole’s accretion disk or ergosphere play an important role in the launching, acceleration, and collimation of active galactic nuclei (AGN ...
Sol N. Molina+3 more
doaj +1 more source
COMMISSION 8: ASTROMETRY [PDF]
Gaia is continuing well with its development and construction and is expected to achieve parallax accuracies of about 10 to 300 muas for 6 to 20 mag. It is scheduled to launch in 2013.
Evans, Dafydd W.+9 more
openaire +2 more sources
Revisiting the Excitation of Free Core Nutation
Abstract Earth possesses a Poincaré mode called Free Core Nutation (FCN) due to the misalignment of the rotation axes of the mantle and fluid outer core. FCN is the primary signal in the observations of Celestial Pole Offsets (CPO) and maintained by geophysical mechanisms that are yet to be understood. Earlier studies suggested an origin in Atmospheric
Mostafa Kiani Shahvandi+4 more
wiley +1 more source
Direct-imaging Discovery of a Substellar Companion Orbiting the Accelerating Variable Star HIP 39017
We present the direct-imaging discovery of a substellar companion (a massive planet or low-mass brown dwarf) to the young, γ Doradus ( γ Dor)-type variable star HIP 39017 (HD 65526). The companion’s SCExAO/CHARIS JHK (1.1–2.4 μ m) spectrum and Keck/NIRC2
Taylor L. Tobin+25 more
doaj +1 more source
Work is done with Epson Expression 10000XL scanner of Astronomical Institute (AI) of theAcademyofSciencesofUzbekistan. The plates were exposed with theNormalastrograph (D/F = 330mm / 3467mm, M = 59.56"/mm). The digitization of plates with(16x16)
M. M. Muminov+5 more
doaj +1 more source
Abstract We present James Webb Space Telescope observations of the globular cluster NGC 6397 and use them to extend to infrared wavelengths the characterization of the cluster's entire white dwarf (WD) cooling sequence (CS). The data allows us to probe fundamental astrophysical WD properties and to search for evidence in their colors for (or against ...
L. R. Bedin+11 more
wiley +1 more source