The advantages of identifying the calibrator first, and then
restricting phase-reference observations to nearby targets are
considerable:
by focusing on one small field, the long telescope slew times usually
associated with snapshot surveys are eliminated and the
task of optimised scheduling is greatly simplified,
by careful selection of a ``model'' calibrator, the data
analysis can be largely automated and high SNR (delay, rate and
phase) solutions can be obtained with only modest integration times,
the offset between the source and the calibrator is typically much
less than $1.5^{\circ}$ even for relatively large samples,
gains in observing efficiency are not limited to radio observations
but are also true for follow-up observations at other wave-bands
(in particular, multi-fibre optical spectroscopy).
Last modified: May 20, 1997
JIVE Home Page
Questions ? Comments ? e-mail Mike Garrett