UBVRI observations of the flickering of RS Ophiuchi at Quiescence

UBVRI Photometric Standard Stars Around the Celestial Equator: Updates and Additions

UCAC3 Proper Motion Survey. I. Discovery of New Proper Motion Stars in UCAC3 with 0.40 "/yr > mu >= 0.18 "/yr between Declinations -90 deg and -47 deg

UCAC3 Proper Motion Survey. II. Discovery Of New Proper Motion Stars In UCAC3 With 0.40" yr^-1 > mu >= 0.18" yr^-1 Between Declinations -47 deg and 00 deg

UKIDSS detections of cool brown dwarfs - proper motions of 14 known $>$T5 dwarfs and discovery of three new T5.5-T6 dwarfs

ULAS J141623.94+134836.3: a Blue T Dwarf Companion to a Blue L Dwarf

Ultra-bright optical transients are linked with type Ic supernovae

Ultra-low Amplitude Variables in the LMC -- Classical Cepheids, Pop. II Cepheids, RV Tau Stars and Binary Variables

Ultra-soft sources as supernova type Ia progenitors

Ultracool Dwarf Science from Widefield Multi-Epoch Surveys

Ultracool Field Brown Dwarf Candidates Selected at 4.5 microns

Ultraviolet and extreme-ultraviolet line ratio diagnostics for O IV

Ultraviolet Coronagraph Spectroscopy: A Key Capability for Understanding the Physics of Solar Wind Acceleration

Ultraviolet Study of the Active Interacting Binary Star R Arae using Archival IUE Data

Ultraviolet variability of the mCP star 56 Arietis

Ultraviolet-Selected Field and Pre-Main-Sequence Stars Towards Taurus and Upper Scorpius

Umbral Dots Observed in Photometric Images taken with 1.6 m Solar Telescope

Umbral Dynamics in the Near Infrared Continuum

Uncertainties and robustness of the ignition process in type Ia supernovae

Uncertainties and systematics in stellar evolution models of Red Giant Stars