No abstract

No abstract

The Hipparcos satellite made measurements of over 9734 known double stars, 3406 new double stars, and 11,687 unresolved but possible double stars. The high angular resolution a †orded by speckle interferometry makes it an efficient means to conÐrm these systems from the ground, which were Ðrst discovered from space. Because of its coverage of a di †erent region of angular separationÈmagnitude di †erence (o-*m) space, speckle interferometry also holds promise to ascertain the duplicity of the unresolved Hipparcos "" problem ÏÏ stars. Presented are observations of 116 new Hipparcos double stars and 469 Hipparcos "" problem stars,ÏÏ as well as 238 measures of other double stars and 246 other high-quality nondetections. Included in these are observations of double stars listed in the Tycho-2 Catalogue and possible grid stars for the Space Interferometry Mission.

The results of 1657 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 1111 mean relative positions and range in separation from 0B16 to 16B99, with a median separation of 1B65. This is the 12th in a series of papers presenting measurements obtained with this system and covers the period 2005 January 3YDecember 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 Coronae Borealis (STF 1937) we determine masses of 1.207 and 1.077 M and an orbital parallax of 54.95 mas.

No abstract

The StarScan machine at the U.S. Naval Observatory (USNO) completed measuring photographic astrograph plates to allow determination of proper motions for the USNO CCD Astrograph Catalog (UCAC) program. All applicable 1940 AGK2 plates, about 2200 Hamburg Zone Astrograph plates, 900 Black Birch (USNO Twin Astrograph) plates, and 300 Lick Astrograph plates have been measured. StarScan comprises of a CCD camera, telecentric lens, air-bearing granite table, stepper motor screws, and Heidenhain scales to operate in a step-stare mode. The repeatability of StarScan measures is about 0.2 µm. The CCD mapping as well as the global table coordinate system has been calibrated using a special dot calibration plate and the overall accuracy of StarScan x, y data is derived to be 0.5 µm. Application to real photographic plate data shows that position information of at least 0.65 µm accuracy can be extracted from course grain 103a-type emulsion astrometric plates. Transformations between "direct" and "reverse" measures of fine grain emulsion plate measures are obtained on the 0.3 µm level per well exposed stellar image and coordinate, which is at the limit of the StarScan machine.

No abstract

The results of 3056 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 a thousand short-exposure images. These observations are averaged into 1675 mean relative positions and range in separation from 0B19 to 45B21, with a median separation of 2B99. This is the ninth in a series of papers presenting measures obtained with this system and covers the period 2002 January 1 through 2002 December 29. Included in these data are 28 older measures whose positions were previously deemed possibly aberrant but are no longer classified this way following a confirming observation. Nine of these systems have new orbital elements, which are presented here as well.