Speckle interferometry of new and problem Hipparcos binaries.: II.: Observations obtained in 1998-1999 from McDonald Observatory

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 afforded by speckle interferometry makes it an efficient means to confirm these systems from the ground, which were first discovered from space. Because of its coverage of a different region of angular separation-magnitude difference (rho-Deltam) space, speckle interferometry also holds promise to ascertain the duplicity of the unresolved Hipparcos problem stars. Presented are observations of 116 new Hipparcos double stars and 469 Hipparcos problem stars, 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.