Orientation Parameters of the Cepheid System in the Galaxy
  Based on the distribution of long-period Cepheids, we have redetermined the
orientation parameters of their principal plane in the Galaxy. Based on 299
Cepheids with heliocentric distances $r<20$ kpc and pulsation periods
$P\geq5^d$, we have found the directions of the three principal axes of the
position ellipsoid:
  $L_1=281.0\pm0.1^\circ,$ $B_1=-1.9\pm0.1^\circ,$
  $L_2= 11.0\pm0.7^\circ,$ $B_2=0.2\pm0.1^\circ$ and
  $L_3=275.9\pm0.7^\circ,$ $B_3=88.1\pm0.1^\circ$. Thus, the line of nodes
$l_\Omega=L_3+90^\circ=5.9^\circ$ is very close to the direction to the
Galactic center; the Cepheid symmetry plane is inclined to the Galactic plane
approximately by $-2^\circ$ in the direction of the first axis ($L_1$). The
direction of the line of nodes found from old Cepheids ($P<5^d$) differs
significantly and is $l_\Omega=298^\circ$. The elevation of the Sun above the
Galactic plane has been estimated from 365 closer stars ($r<4$ kpc) without any
constraint on the pulsation period to be $h_\odot=23\pm5$ pc.
