  Near-Eddington accretion rates onto low-mass black holes are thought to be a
prime driver of the multi-wavelength properties of the narrow-line Seyfert 1
(NLS1) population of active galactic nuclei (AGN). Orientation effects have
repeatedly been considered as another important factor involved, but detailed
studies have been hampered by the lack of measured viewing angles towards this
type of AGN. Here we present multi-epoch, 15 GHz VLBA images (MOJAVE program)
of the radio-loud and Fermi/LAT-detected NLS1 galaxy 1H 323+342. These are
combined with single-dish, multi-frequency radio monitoring of the source's
variability, obtained with the Effelsberg 100-m and IRAM 30-m telescopes, in
the course of the F-GAMMA program. The VLBA images reveal 6 components with
apparent peeds of ~1 to ~7 c, and one quasi-stationary feature. Combining the
obtained apparent jet speed ($\beta_{app}$) and variability Doppler factor
($D_{var}$) estimates together with other methods, we constrain the viewing
angle towards 1H 0323+342 to $\theta \leq 4 - 13$ deg. Using literature values
of $\beta_{app}$ and $D_{var}$, we also deduce a viewing angle of $\leq$ 8-9
deg towards another radio- and {\gamma}-ray-loud NLS1, namely SBS 0846+513.

High Energy Astrophysical Phenomena