The Eclipse Expedition of the Naval Observatory

Science ◽  
1929 ◽  
Vol 69 (1780) ◽  
pp. 153-154
Keyword(s):  
Naval Observatory

scholarly journals CPC2 Reduction with Hipparcos and Proper Motions in The Southern Hemisphere

1998 ◽  
Vol 11 (1) ◽  
pp. 551-551
Author(s):  
N. Zacharias ◽  
M.I. Zacharias ◽  
C. de Vegt ◽  
C.A. Murray
Keyword(s):  
Southern Hemisphere ◽  
Systematic Errors ◽  
Reference Star ◽  
Proper Motions ◽  
Positional Accuracy ◽  
Star Catalog ◽  
Naval Observatory ◽  
Celestial Reference System ◽  
First Time ◽  
Better Than

The Second Cape Photographic Catalog (CPC2) contains 276,131 stars covering the entire Southern Hemisphere in a 4-fold overlap pattern. Its mean epoch is 1968, which makes it a key catalog for proper motions. A new reduction of the 5687 plates using on average 40 Hipparcos stars per plate has resulted in a vastly improved catalog with a positional accuracy of about 40 mas (median value) per coordinate, which comes very close to the measuring precision. In particular, for the first time systematic errors depending on magnitude and color can be solved unambiguously and have been removed from the catalog. In combination with the Tycho Catalogue (mean epoch 1991.25) and the upcoming U.S. Naval Observatory CCD Astrograph Catalog (UCAC) project proper motions better than 2 mas/yr can be obtained. This will lead to a vastly improved reference star catalog in the Southern Hemisphere for the final Astrographic Catalogue (AC) reductions, which will then provide propermotions for millions of stars when combined with new epoch data. These data then will allow an uncompromised reduction of the southern Schmidt surveys on the International Celestial Reference System (ICRS).

Speckle Interferometry at the US Naval Observatory. IX.

2004 ◽  
Vol 127 (1) ◽  
pp. 539-548 ◽  
Author(s):  
Brian D. Mason ◽  
William I. Hartkopf ◽  
Gary L. Wycoff ◽  
Dan Pascu ◽  
Sean E. Urban ◽  
...  
Keyword(s):  
Speckle Interferometry ◽  
Naval Observatory ◽  
The Us

The U. S. Naval Observatory

Science ◽  
1909 ◽  
Vol 30 (781) ◽  
pp. 880-881
Keyword(s):  
Naval Observatory

scholarly journals Characterising open clusters in the solar neighbourhood with the Tycho-Gaia Astrometric Solution

2018 ◽  
Vol 615 ◽  
pp. A49 ◽  
Author(s):  
T. Cantat-Gaudin ◽  
A. Vallenari ◽  
R. Sordo ◽  
F. Pensabene ◽  
A. Krone-Martins ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Markov Chain ◽  
High Probability ◽  
Open Clusters ◽  
Distance Modulus ◽  
The Sun ◽  
Proper Motions ◽  
Orbital Parameters ◽  
Naval Observatory ◽  
Galactic Potential

Context. The Tycho-Gaia Astrometric Solution (TGAS) subset of the first Gaia catalogue contains an unprecedented sample of proper motions and parallaxes for two million stars brighter than G ~ 12 mag. Aims. We take advantage of the full astrometric solution available for those stars to identify the members of known open clusters and compute mean cluster parameters using either TGAS or the fourth U.S. Naval Observatory CCD Astrograph Catalog (UCAC4) proper motions, and TGAS parallaxes. Methods. We apply an unsupervised membership assignment procedure to select high probability cluster members, we use a Bayesian/Markov Chain Monte Carlo technique to fit stellar isochrones to the observed 2MASS JHKS magnitudes of the member stars and derive cluster parameters (age, metallicity, extinction, distance modulus), and we combine TGAS data with spectroscopic radial velocities to compute full Galactic orbits. Results. We obtain mean astrometric parameters (proper motions and parallaxes) for 128 clusters closer than about 2 kpc, and cluster parameters from isochrone fitting for 26 of them located within a distance of 1 kpc from the Sun. We show the orbital parameters obtained from integrating 36 orbits in a Galactic potential.

Speckle Interferometry at the US Naval Observatory. XIII.

2007 ◽  
Vol 134 (4) ◽  
pp. 1671-1678 ◽  
Author(s):  
Brian D. Mason ◽  
William I. Hartkopf ◽  
Gary L. Wycoff ◽  
Gary Wieder
Keyword(s):  
Speckle Interferometry ◽  
Naval Observatory ◽  
The Us

Speckle Interferometry at the US Naval Observatory. I.

1997 ◽  
Vol 111 (1) ◽  
pp. 289-334 ◽  
Author(s):  
Geoffrey G. Douglass ◽  
Robert B. Hindsley ◽  
Charles E. Worley
Keyword(s):  
Speckle Interferometry ◽  
Naval Observatory ◽  
The Us

scholarly journals U.S. Naval Observatory Double Star CD 2006.5

2006 ◽  
Vol 2 (S240) ◽  
pp. 575-580 ◽  
Author(s):  
Brian D. Mason ◽  
William I. Hartkopf
Keyword(s):  
Binary Stars ◽  
Double Star ◽  
List Type ◽  
Star Catalog ◽  
Naval Observatory ◽  
Scale Calibration ◽  
Linear Elements ◽  
Visual Binary Stars ◽  
Star Catalogs ◽  
Magnitude Difference

AbstractThe U.S. Naval Observatory has produced its second CDROM of double star catalogs. This successor to the 2001.0 CDROM includes the latest versions (June 30 2006) of four major double star catalogs maintained at the USNO: •Washington Double Star Catalog (WDS),•Second Photometric Magnitude Difference Catalog,•Fourth Catalog of Interferometric Measurements of Binary Stars, and•Sixth Catalog of Orbits of Visual Binary Stars.Each of these catalogs had seen significant changes during the past six years; for example, the WDS has grown by over 150,000 measures and the number of systems in the Interferometric Catalog has nearly doubled. Other improvements include precise coordinates for the vast majority of systems, as well as new observing lists for tens of thousands of “neglected” doubles.Also included on this CDROM is a Catalog of Linear Elements for several hundred optical pairs. These elements should prove useful for improving the components' proper motions, as well as providing scale calibration out to several tens of arcseconds.As was done with its predecessor, the new CDROM is automatically distributed free of charge to members of the double star community and to astronomy libraries. Others may receive a complementary copy upon request.

Sign in / Sign up

Export Citation Format

Share Document