Residuals obtained from the differences between the maps in Fig. 2, as indicated on top of each frame. From left to right and up to down, the rms noise in μJy beam^-1 is 28, 28, 29.6, 28, 29, and 29, respectively. Contour levels are given in units of rms noise at the bottom of each panel. All residuals tend to be well aligned with the jet position angle. The map corresponding to the 2000 epoch has not been used because 1E 1740.7−2942 was not at the phase center and the primary beam corrections would then render the difference maps meaningless.

Attempt to fit the 1992 location of the most prominent four condensations in the 1E 1740.7−2942 jet with a simple straight jet line model passing through the central core, which results in a rather poor 4.4 value of .

Left: attempts to fit the 1992 to 2000 observing epochs of the 1E 1740.7−2942 radio jets using rectilinear trajectories (thick lines). All of these emanate from the central core located at the intersection of the dashed lines. The brown crosses denote the observed jet path based on the maxima skeleton discussed in the text. The horizontal scale has been expanded to better show the straight line displacements from the jet flow. The reduced value of the combined five epoch fit amounts to 2.2. Right: fits to the 1992 to 2000 observing epochs of the 1E 1740.7−2942 radio jets based on the Hjellming & Johnston (1981) precessing twin jet model (thick lines). To facilitate an easy comparison, the outline of these plots is the same as in the left panel except for the fitting curves. We used the corresponding model parameter values given in right column of Table 2. The fit agreement with the observed jet paths appears to be significantly better here, with a reduced value as low as 0.91.