Results 71 to 80 of about 3,440 (204)
Corrected μβ for stars of Hipparcos catalogue from independent latitude observations over many decades [PDF]
Serbian Astronomical Journal, 2011 During the last century, there were many so-called independent latitude (IL) stations with the observations which were included into data of a few international organizations (like Bureau International de l'Heure - BIH, International Polar ...
Damljanović G., Milić I.S.
doaj +1 more source
arXiv: Astrophysics, 2005 General relativistic effects in astrophyiscal systems have been detected thanks to accurate astrometric measurements. We outline some keystones of astrometry such as stellar aberration (argument development during the years 1727-1872); Mercury's perihelion precession (1845-1916); solar disk oblateness (1966-2001); relativistic light deflection (1916 ...
openaire +3 more sources
Nature in Seclusion. The Monastic Republic of Letters in Southern Germany**
Berichte zur Wissenschaftsgeschichte, Volume 47, Issue 3, Page 215-241, September 2024.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
Odessa Astronomical Publications, 2014 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
Astrometry during the past 100 years [PDF]
arXiv, 2011 The reports from 2008: "Astrometry and optics during the past 2000 years", are available at arXiv and at my website: www.astro.ku.dk/~erik/History.pdf . Here are now further contributions to the history of astrometry related to space astrometry. The development of photoelectric astrometry is followed from an experiment in 1925 up to the Hipparcos ...
arxiv
Journal of Geophysical Research: Space Physics, Volume 129, Issue 9, September 2024.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
Galaxies, 2017 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
Astrometry 1960-80: from Hamburg to Hipparcos [PDF]
arXiv, 2014 Astrometry, the most ancient branch of astronomy, was facing extinction during much of the 20th century in the competition with astrophysics. The revival of astrometry came with the European astrometry satellite Hipparcos, approved by ESA in 1980 and launched 1989.
arxiv
Revisiting the Excitation of Free Core Nutation
Journal of Geophysical Research: Solid Earth, Volume 129, Issue 9, September 2024.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
Radio Astrometry towards the Nearby Universe with the SKA [PDF]
arXiv, 2016 This chapter summarizes radio astrometry in relation to current very long baseline interferometry (VLBI) projects and describes its perspectives with the SKA. The scientific goals of the astrometry with the SKA have been discussed in the international and Japanese communities of researchers, whose major issues are shown here.
arxiv