  A cataclysmic variable is a binary system consisting of a white dwarf that
accretes material from a secondary object via the Roche-lobe mechanism. In the
case of long enough observation, a detailed temporal analysis can be performed,
allowing the physical properties of the binary system to be determined. We
present an XMM-Newton observation of the dwarf nova HT Cas acquired to resolve
the binary system eclipses and constrain the origin of the X-rays observed. We
also compare our results with previous ROSAT and ASCA data. After the spectral
analysis of the three EPIC camera signals, the observed X-ray light curve was
studied with well known techniques and the eclipse contact points obtained.
  The X-ray spectrum can be described by thermal bremsstrahlung of temperature
$kT_1=6.89 \pm 0.23$ keV plus a black-body component (upper limit) with
temperature $kT_2=30_{-6}^{+8}$ eV. Neglecting the black-body, the bolometric
absorption corrected flux is $F^{\rm{Bol}}=(6.5\pm 0.1)\times10^{-12}$ erg
s$^{-1}$ cm$^{-2}$, which, for a distance of HT Cas of 131 pc, corresponds to a
bolometric luminosity of $(1.33\pm 0.02)\times10^{31}$ erg s$^{-1}$.
  The study of the eclipse in the EPIC light curve permits us to constrain the
size and location of the X-ray emitting region, which turns out to be close to
the white dwarf radius. We measure an X-ray eclipse somewhat smaller (but only
at a level of $\simeq 1.5 \sigma$) than the corresponding optical one. If this
is the case, we have possibly identified the signature of either high latitude
emission or a layer of X-ray emitting material partially obscured by an
accretion disk.
