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The WHT telescope computer has a standard catalogue containing accurate
positions and proper motions for astrometric, photometric and
spectrophotometric standards. This is described in detail in La Palma
Technical Note 85, which is updated periodically. The main elements of
the catalogue are:
Use of the catalogue positions will speed up acquisition and avoid
potential difficulties with inaccurate positions and proper motions
given in the literature.
- A grid of bright stars with extremely accurate positions, selected
from the FK5 catalogue and used to check the pointing of the telescope.
- A similar grid of fainter stars (V 9) from AGK3 and
CPC2, with slightly less accurate positions, but suitable for detectors
which saturate on the bright grid.
- Spectrophotometric standards, selected from the literature. All
have accurate positions and the flux distributions and references to
original measurements are collected in La Palma Technical Note 65.
- UBVRI photometric standards selected from Landolt ( Astronomical
Journal 88, 439, 1983, and
Astronomical Journal 104, 340, 1992), again
with accurate positions.
- A few useful photometric sequences for calibration of CCD frames.
- Some fields with a paucity of bright stars, to be used for sky
- Astrometric fields for calibration of detector geometry.
Tue Aug 15 16:42:46 BST 1995