UBVRI Landolt Standards
These data are a selection of stars supplied by Arlo Landolt to serve as
bright standards of the UBVRI photometric system. They provide internally
consistent homogeneous broadband standards for the Johnson-Kron-Cousins photometric system for
telescopes of intermediate and large size in both hemispheres. The filter bands have the following
effective wavelengths: U, 3600Å; B, 4400Å; V, 5500Å; R, 6400Å; I, 7900Å.
The positions are taken from the
Naval Observatory Merged Astronomical Database (NOMAD). Positions are convered to the
epoch, equator, and equinox of the middle of the current year; radial velocities are included in the
calculation where available.
The Astronomical Almanac Online! 2013