1.2k citations · 2.2k across the 7 of their papers we have counts for
7 papers
Radio-Optical Reference Frame Link Using the US Naval Observatory Astrograph and Deep CCD Imaging
Norbert Zacharias, Marion I. Zacharias
Between 1997 and 2004 several observing runs were conducted mainly with the CTIO 0.9 m to image ICRF counterparts (mostly QSOs) in order to determine accurate optical positions. Co…
Pluto's Atmosphere Does Not Collapse
C. B. Olkin, L. A. Young, D. Borncamp +21
Combining stellar occultation observations probing Pluto's atmosphere from 1988 to 2013 and models of energy balance between Pluto's surface and atmosphere, we conclude that Pluto'…
The Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)
Norbert Zacharias, Charlie Finch, Terry Girard +4
The fourth United States Naval Observatory (USNO) CCD Astrograph Catalog, UCAC4 was released in August 2012 (double-sided DVD and CDS data center Vizier catalog I/322). It is the f…
The Third US Naval Observatory CCD Astrograph Catalog (UCAC3)
N. Zacharias, C. Finch, T. Girard +27
The third US Naval Observatory (USNO) CCD Astrograph Catalog, UCAC3 was released at the IAU General Assembly on 2009 August 10. It is the first all-sky release in this series and c…
The second US Naval Observatory CCD Astrograph Catalog (UCAC2)
N. Zacharias, S. E. Urban, M. I. Zacharias +4
The second USNO CCD Astrograph Catalog, UCAC2 was released in July 2003. Positions and proper motions for 48,330,571 sources (mostly stars) are available on 3 CDs, supplemented wit…
Comparing Tycho-2 Astrometry with UCAC1
Norbert Zacharias, Marion I. Zacharias, Sean E. Urban +1
The Tycho-2 Catalogue, released in February 2000, is based on the ESA Hipparcos space mission data and various ground-based catalogs for proper motions. An external comparison of t…