We have compiled L' (3.4-4.1 microns) and M' (4.6-4.8 microns) photometry of 63 single and binary M, L, and T dwarfs obtained at the United Kingdom Infrared Telescope using the Mauna Kea Observatory filter set. This compilation includes new L' measurements of eight L dwarfs and 13 T dwarfs and new M' measurements of seven L dwarfs, five T dwarfs, and the M1 dwarf Gl 229A. These new data increase ...
We present preliminary trigonometric parallaxes and proper motions for 22 L dwarfs and 18 T dwarfs measured using the ASTROCAM infrared imager on the US Naval Observatory (USNO) 1.55 m Strand Astrometric Reflector. The results presented here are based on observations obtained between 2000 September and 2002 November; about half of the objects have an observational time baseline of t 1:3 yr and half t 2:0 yr. Despite these short ...
The accuracy of new charge-coupled-device (CCD) photometry in the Vilnius system of the M67 cluster is analyzed. The observational material was obtained during six observing runs in 1994 to 2001 with the 1-meter telescope of the U.S. Naval Observatory Flagstaff Station. The main task was to establish CCD standards of high accuracy and to eliminate large-scale errors from their CCD photometry. The authors compare their results with the published CCD ...
Seven-color photometry in the Vilnius system has been obtained for 420 stars down to V=16 mag in the area containing the overlapping open clusters NGC 1750 and NGC 1758 in Taurus. Spectral and luminosity classes, color excesses, interstellar extinctions, and interstellar distances are given for 287 stars. The classification of stars is based on their reddening-free Q- parameters. Eighteen stars observed photoelectrically were used as standards. The extinction versus distance ...
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