Results 51 to 60 of about 3,440 (204)

Connecting VLBI and Gaia celestial reference frames

Frontiers in Astronomy and Space Sciences, 2016
The current state of the link problem between radio and optical celestial reference frames is considered.The main objectives of the investigations in this direction during the next few years are the preparation of a comparisonand the mutual orientation ...
Zinovy Malkin
doaj   +1 more source

Uncertainties in Ground‐Based Visual Double Star Measures—II Accuracy of Measures

Astronomische Nachrichten, EarlyView.
ABSTRACT Letchford and White 2025, Paper I, determined the uncertainties in ground‐based historic measures of double stars. In this paper, the accuracy of 26,205 ground‐based measures of 857 visual double stars, made since ∼$$ \sim $$1780, is determined relative to space‐based measures based on positions and proper motion from the HIPPARCOS (via ASCC ...
Graeme L. White, Roderick R. Letchford
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

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

Observations of a Disconnection Event and Other Large‐Scale Disturbances in the Ion Tail of Comet C/2022 E3 (ZTF)

Journal of Geophysical Research: Space Physics, Volume 130, Issue 5, May 2025.
Abstract We analyze five large‐scale tail disturbances in comet C/2022 E3 (ZTF)'s ion tail using images from astrophotographers, tracking specific features within the tail to determine their speeds. We employ a heliosphere model to estimate when the comet crossed the heliospheric current sheet (HCS).
A. Wellbrock, G. H. Jones
wiley   +1 more source

A comparison of participatory science seining and electrofishing for sampling fish assemblages in an urban river

Ecological Solutions and Evidence, Volume 6, Issue 2, April/June 2025.
Venn Diagram of fish species captured by seining and electrofishing. The 10 most frequent species captured in the watershed are represented in the overlapping area as well as an outline of the state of Michigan with the Rouge River watershed highlighted. Both sides have a picture of method collection with a darter on the seining side and a trout on the
Olivia F. Williams, Sally Petrella, Lauren Eaton, Robert Muller, Philip Kukulski, Paul Seelbach, Catherine Riseng, Karen M. Alofs   +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

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

Macho Photometry and Astrometry [PDF]

Symposium - International Astronomical Union, 1995
MACHOs (Massive Astrophysical Compact Halo Objects) have been discovered by their relativistic amplification of light from distant stars as they crossed very near to the line-of-sight. The very few events were detected from more than a billion photometric measurements of millions of stars in the LMC.
Høg, E., Novikov, Igor Dmitrievich, Polnarev, A.G.   +2 more
openaire   +3 more sources

Review of asteroid, meteor, and meteorite‐type links

Meteoritics &Planetary Science, Volume 60, Issue 4, Page 928-973, April 2025.
Abstract With the goal to determine the origin of our meteorites in the asteroid belt, video and photographic observations of meteors have now tracked 75 meteorite falls. Six years ago, there were just hints that different meteorite types arrived on different orbits, but now, the number of orbits (N) is high enough for distinct patterns to emerge.
Peter Jenniskens, Hadrien A. R. Devillepoix   +1 more
wiley   +1 more source