It is well known that IUE spectra taken with long exposures are affected by two kinds of spurious features that mimic emission lines. The so called spectral "artifacts" appear in the same location on every long exposure spectrum and are due to camera phosphorescence (Crenshaw et al. 1990). They are rather sharp and their intensity generally increases with the exposure time. The other pseudo-emission features (blemishes) are instead associated with single events such as cosmic-ray hits and are generally very sharp. The long exposure spectrum of RR Tel (SWP 20246 - 820 min) is contaminated by both these features. A list of the former is given in ADB.
We have checked this list by comparing the same SWP 20246 spectrum with a long exposure high resolution spectrum (SWP 6325) of the cataclysmic variable V 603 Aql that is characterized by an almost featureless continuum with only a few very wide over-imposed emission lines. This makes rather easy to identify the spectral artifacts as those "emission" features which are common to the two spectra. We confirm several of the artifacts found by ADB and we list them in Table 3a but we remark that in many other cases their presence is questionable. It is worth pointing out, however, that some caution should be taken in this context because some aspects related to the "artifacts" presence itself, the repeatibility of such features in different spectra, and the scaling of their intensities with the exposure time seem still unclear (Selvelli et al. 1997).
Incidentally, in this study we have also found clear evidence of several new pseudo-emission features that are common to the two spectra and therefore may be considered as additional spectral artifacts. They are listed in Table 3b.
Another source of pseudo emission features in IUE high resolution spectra of
emission line objects is the over-spilling of strong, saturated emission lines
that may
affect the adjacent order in the echelle spectrum, especially in the range
1175-1300 Å where the separation between adjacent orders is quite small.
We attribute to this mechanism the two emissions at 
1227.8
and
1231.6 identified
as NI in ADB. In our opinion these features are produced by
overspilling of the NV doublet at 1238.82 and
1242.81. This is supported by
the fact
that the observed separation between the two pairs of lines is the same,
4.0 Å, in contrast with the separation between the laboratory values of the
NI lines which is 3.79 Å. Also, the
continuum level in the region 
is below zero,
another IUE "artifact" produced by the
subtraction of an excess of inter-order background, caused by the over-spilling
of signal from the successive order (that of the NV lines, where a wide
emission is also present).
Another pseudo-emission feature in the same SWP 20246 spectrum is observed
at 1207.5 Å and is produced by overspilling of the OV 1218.35
line in the
successive order, while the feature at 1205.7 Å is associated with the
geo-coronal 
line filling the small aperture.