  Photometric parameters of stellar disks and bulges for several edge-on
galaxies from the Catalog of Flat Galaxies (FGC) were determined. We discuss a
difference between photometric parameters of LSB and HSB galaxies from our
sample.
  Also we present results of R CCD photometry of edge-on galaxy RFGC 3647.
Deprojecting this galaxy we show that it has thin LSB disk (central surface
brightness $22^m.2$ in R) and high ratio of radial to vertical scale lengths.
It is shown that initially gaseous disk of the galaxy was unstable and its
velocity dispersion was low. Stellar disk of this LSB galaxy was not heated
significantly since that time.

Astrophysics