The results of 1683 speckle interferometric observations of double stars, made with the 26 inch (66 cm) refractor of the US Naval Observatory, are presented. Each speckle interferometric observation of a system represents a combination of over 2000 short-exposure images. These observations are averaged into 805 mean relative positions and range in separation from 0.23" to 43.34", with a median separation of 4.33". This is the 11th in a series of papers presenting measurements obtained with this system and covers the period 2004 January 4-December 30. Included in these data are two older measurements whose positions were previously deemed possibly aberrant but are no longer classified this way following a confirming observation. Two of these systems have new orbital elements, which are also presented here.
The results of 1657 speckle interferometric observations of double stars, made with the 26-inch (66cm) refractor of the US Naval Observatory, are presented. Each speckle interferometric observation of a system represents a combination of over 2000 short-exposure images. These observations are averaged into 1111 mean relative positions and range in separation from 0.16" to 16.99", with a median separation of 1.65". This is the 12th in a series of papers presenting measurements obtained with this system and covers the period 2005 January 3-December 29. Included in these data are 30 older measurements whose positions were previously deemed possibly aberrant but are no longer classified this way following a confirming observation. Sixteen of these systems have new orbital elements, which are presented here as well. For eta Coronae Borealis (STF 1937) we determine masses of 1.207 and 1.077M_{sun}_ and an orbital parallax of 54.95mas.
The results of 1424 speckle interferometric observations of double stars, made with the 26 inch (66cm) refractor of the US Naval Observatory, are presented. Each speckle interferometric observation of a system represents a combination of over 2000 short-exposure images. These observations are averaged into 1053 mean relative positions and range in separation from 0.36" to 61.92", with a median separation of 10.31". This is the 13th in a series of papers presenting measurements obtained with this system and covers the period 2006 January 12-December 29. Included in these data are nine older measurements whose positions were previously deemed possibly aberrant but are no longer classified this way following a confirming observation. This paper also includes the first data obtained using a new "secondary" camera, designed and built at USNO.
The results of 2033 intensified CCD observations of double stars, made with the 26 inch refractor of the U.S. Naval Observatory, are presented. Each observation of a system represents a combination of over 2000 short-exposure images. These observations are averaged into 1297 mean relative positions and range in separation from 0.54" to 58.96", with a mean separation of 14.99". This is the 14th in this series of papers and covers the period 2007 January 17 through 2007 December 31. The first two resolutions of closer companions to previously known wider pairs are also presented.
Results of 2433 intensified CCD observations of double stars, made with the 26 inch refractor of the U.S. Naval Observatory, are presented. Each observation of a system represents a combination of over 2000 short-exposure images. These observations are averaged into 1013 mean relative positions and range in separation from 0.96" to 58.05", with a mean separation of 13.50". This paper is the 15th in the series of papers and covers the period 2008 January 3 through 2008 December 21.
The results of 1031 speckle-interferometric observations of double stars, made with the 26 inch refractor of the U.S. Naval Observatory, are presented. Each speckle-interferometric observation of a system represents a combination of over two thousand short-exposure images. These observations are averaged into 457 mean relative positions and range in separation from 0.15" to 16.94", with a median separation of 3.03". The range in V-band magnitudes for the primary (secondary) of observed targets is 3.1-12.9 (3.2-13.3).
The results of 3362 intensified CCD observations of double stars, made with the 26 inch refractor of the U.S. Naval Observatory, are presented. Each observation of a system represents a combination of over 2000 short-exposure images. These observations are averaged into 1970 mean relative positions and range in separation from 0.78" to 72.17", with a mean separation of 14.76". This is the 17th in this series of papers and covers the period 2010 January 6 through December 20. Also presented are 10 pairs that are resolved for the first time.
Results are presented of 4222 intensified CCD observations of double stars, made with the 26 inch refractor of the U.S. Naval Observatory in 2013 and 2014. These observations are averaged into 2335 mean relative positions and range in separation from 0.53'' to 83.90'', with a median separation of 11.42''. This is the 20th in this series of papers and covers the period 2013 January 4 through 2014 December 18. Also presented are 13 pairs which are measured for the first time, 12 pairs which appear to be lost, linear elements for 17 pairs, and orbital elements for five additional pairs. Finally, we investigated apparent systematic residuals to earlier measures in this series, and modify scale factors for closer pairs observed between 1990 and the present.
The results of 2408 intensified CCD observations of double stars, made with the 26 inch refractor of the U.S. Naval Observatory, are presented. Each observation of a system represents a combination of over 2000 short-exposure images. These observations are averaged into 1602 mean relative positions and range in separation from 1.94'' to 107.41'', with a median separation of 11.96''. This is the twenty-first in this series of papers and covers the period from 2015 January 13 through 2015 December 19. Significant instrumentation changes are reported in this paper.
The results of speckle interferometric measurements of binary and multiple stars conducted in 2008 and 2009 at the Blanco and SOAR 4m telescopes in Chile are presented. A total of 1898 measurements of 1189 resolved pairs or sub-systems and 394 observations of 285 un-resolved targets are listed. We resolved for the first time 48 new pairs, 21 of which are new sub-systems in close visual multiple stars.
