  The detectability of moons of extra-solar planets is investigated, focussing
on the time-of-arrival perturbation technique, a method for detecting moons of
pulsar planets, and the photometric transit timing technique, a method for
detecting moons of transiting planets. Realistic thresholds are derived and
analysed in the in the context of the types of moons that are likely to form
and be orbitally stable for the lifetime of the system.
  For the case of the time-of-arrival perturbation technique, the analysis is
conducted in two stages. First, a preliminary investigation is conducted
assuming that planet and moon's orbit are circular and coplanar. This analysis
is then applied to the case of the pulsar planet PSR B1620-26 b, and used to
conclude that a stable moon orbiting this pulsar planet could be detected, if
its mass was >5% of its planet's mass (2.5 Jupiter masses), and if the
planet-moon distance was ~ 2% of the planet-pulsar separation (23 AU).
Time-of-arrival expressions are then derived for mutually inclined as well as
non-circular orbits.
  For the case of the photometric transit timing technique, a different
approach is adopted. First, analytic expressions for the timing perturbation
due to the moon are derived for the case where the orbit of the moon is
circular and coplanar with that of the planet and where the planet's orbit is
circular and aligned to the line-of-sight, circular and inclined with respect
to the line-of-sight or eccentric and aligned to the line-of-sight. Second, the
timing noise is investigated analytically, for the case of white photometric
noise, and numerically, using SOHO lightcurves, for the case of realistic and
filtered realistic photometric noise. [...] Abstract truncated due to the
limitations of astroph. See full abstract in the thesis.
