Results 51 to 60 of about 7,595 (254)

Astrometry in China [PDF]

Symposium - International Astronomical Union, 1986
The space age and modern technology have opened a new era for astrometry. A great amount of modern, precise astrometric data and approaches is urgently needed not only for astrophysics but also for Earth Science research. The Astrometric Community looks forward to establishing a precisely specified uniform celestial frame of reference for all purposes,
openaire   +2 more sources

Uncertainties in Ground‐Based Visual Double Star Measures

Astronomische Nachrichten, Volume 346, Issue 2, February 2025.
ABSTRACT Stellar masses are found from the orbital elements of binary systems which are, in turn, computed from weighted astrometric measures. Astrometric measures of double stars (their position angle and separation) rarely include uncertainties, and published binary star orbits rarely include the weighting systems used in the determination of the ...
Roderick R. Letchford, Graeme L. White
wiley   +1 more source

Precision astrometry with adaptive optics [PDF]

SPIE Proceedings, 2008
We investigate the limits of ground-based astrometry with adaptive optics using the core of the Galactic globular cluster M5. Adaptive optics systems provide near diffraction-limit imaging with the world's largest telescopes. The substantial improvement in both resolution and signal-to-noise ratio enables high-precision astrometry from the ground.
Cameron, P. B., Britton, M. C., Kulkarni, S. R.   +2 more
openaire   +9 more sources

JWST Imaging of the Closest Globular Clusters—V. The White Dwarfs Cooling Sequence of M4

Astronomische Nachrichten, Volume 346, Issue 2, February 2025.
ABSTRACT We combine infrared (IR) observations collected by the James Webb Space Telescope with optical deep images by the Hubble Space Telescope taken ~20 years earlier to compute proper‐motion membership for the globular cluster (GC) M4 (NGC 6121) along its entire white dwarf (WD) cooling sequence (CS).
Luigi R. Bedin, Mattia Libralato, Maurizio Salaris, Domenico Nardiello, Michele Scalco, Massimo Griggio, Jay Anderson, Pierre Bergeron, Andrea Bellini, Roman Gerasimov, Adam J. Burgasser, Daniel Apai   +11 more
wiley   +1 more source

The Orbits of Uranus, Its Satellites and Rings, the Gravity Field of the Uranian System, and the Orientation of the Poles of Uranus and Its Satellites

The Astronomical Journal
R. A. Jacobson determined the orbits of the Uranian satellites, the masses of Uranus and its satellites, and the orientation of the pole of Uranus from Earth-based astrometry, Earth-based ring occultations, and observations acquired with the Voyager 2 ...
Robert A. Jacobson, Ryan S. Park
doaj   +1 more source

Revisiting Variable Stars Near Globular Clusters South of −29° Declination

Astronomische Nachrichten, Volume 346, Issue 2, February 2025.
ABSTRACT We review an often‐cited but seldom‐accessed catalogue by Fourcade and Laborde (1966) of 785 variable stars near 47 southern Galactic globular clusters, and recover the locations of 85 stars that were not incorporated into subsequent variable star catalogues and hence have become “lost” to the literature.
Andrew C. Layden, Julia Evangelista, Sakshi Gupta, Mithilesh Mittameda, Eva Mulloy, Sohan I. Muslim, Tiyinoluwa Olushola‐Alao, Akul Rishi   +7 more
wiley   +1 more source

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

Astrometry of the Omega Centauri Hubble Space Telescope Calibration Field [PDF]

, 2000
Astrometry, on the International Celestial Reference Frame (epoch J2000.0), is presented for the Walker (1994, PASP, 106, 828) stars in the Omega Centauri (= NGC 5139 = C1323-1472) Hubble Space Telescope Wide Field/Planetary Camera (WF/PC) calibration field of Harris et al. (1993, AJ, 105, 1196). Harris et al.
arxiv   +1 more source

Multi‐Instrument and SAMI3‐TIDAS Data Assimilation Analysis of Three‐Dimensional Ionospheric Electron Density Variations During the April 2024 Total Solar Eclipse

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, Joseph Huba, Shun‐Rong Zhang, Anthea J. Coster, Philip J. Erickson, Larisa P. Goncharenko, Juha Vierinen, William Rideout   +7 more
wiley   +1 more source

Optimizing image processing for modern wide field surveys: enhanced data management based on the LSST science pipelines

Frontiers in Astronomy and Space Sciences
Introduction: In recent decades, numerous large survey projects have been initiated to enhance our understanding of the cosmos. Among these, the Vera C.
Yuanyu Hong, Yuanyu Hong, Chao Yang, Chao Yang, Miaomiao Zhang, Yanpeng Chen, Yanpeng Chen, Binyang Liu   +7 more
doaj   +1 more source