  We have selected a field from the VLA FIRST Survey which is typical in all
aspects except one: it contains a bright, but extremely compact VLBI calibrator
- J1159+291. 127 unresolved FIRST sources with $S_{FIRST}\ge 10$ mJy lie within
$2.5^{\circ}$ of this calibrator. $\lambda 6$ cm MERLIN observations with a
resolution $\sim 60$ mas detect around half the sources. These detections form
the basis of a sample of faint but compact radio sources which are ideally
suited to follow-up VLBI observations.

Astrophysics