3 Data reduction

The data were reduced using the package Miriad following standard reduction steps as described in the reference guide by Bob Sault and Neil Killeen (Sault et al. 1995). The data were loaded, bad points flagged, and then split into single source files. The bandpass function and the antenna gains were determined as a function of time to calibrate the data. From the visibilities, images were made using the multi-frequency synthesis technique and robust weighting with a robustness parameter of 0.5, which gives nearly the same sensitivity as natural weighting but with a significantly better beam. First, a low resolution image of the primary beam was made to identify confusing sources. Next, a high resolution image was made including all sources. These maps were CLEANed. Because we had offset the PNe from the field center, we applied the primary beam correction which amounted to about 1% at 6 cm and 2% at 3 cm. Self-calibration was not applied because the flux values of the PNe are too low. Contour plots of the detected PNe are presented in the appendix.