will be better determined for higher peak flux values and smaller PNe. It is also for this reason that we chose to use the value at 6 cm and not at 3 cm, where the resolution is twice as high and the signal to noise per beam lower for extended sources.

We note that the radio positions have a tendency to be offset towards the west of the optical position. In declination there is no clear tendency noticeable in the offsets.

The optical and radio positions agree very well. PNe for which the radio position differs more than 2  in RA or DEC from the optical position are extended and the peak in the radio is usually not centered.

Of the 64 PNe observed, 7 were not detected: JaSt 7, 21, 45, 80, 88, 92, and 96. Most likely they are very extended and have a surface brightness that is too low to be detected in the radio. They are also very faint in the H$\alpha$ images and their H$\alpha$ flux values are very uncertain (Jacoby & Van de Steene 2001, in preparation). All but JaSt 96 were also faint and extended in the \[S III\]$\lambda$9532 images.

  ------ ------------- -------------- 