  Spectroscopic observations of a transit event of an extrasolar planet offer
the opportunity to study the composition of the planetary atmosphere. We
observed a transit of the inflated Hot Jupiter HAT-P-32b with MODS at the LBT
to characterize its atmosphere from 3300 to 10000 AA. A time series of target
and reference star spectra was binned in two broad-band wavelength channels,
from which differential transit light curves were constructed. These broad-band
light curves were used to confirm previous transit parameter determinations. To
derive the planetary transmission spectrum with a resolution of R ~ 60, we
created a chromatic set of 62 narrow-band light curves with an average
wavelength width of about 100 AA. The spectrum was corrected for the
third-light of a near-by M star, whose spectrum was resolved in the individual
exposures. Additionally, we undertook a photometric monitoring campaign of the
host star to correct for the influence of starspots. The transmission spectrum
of HAT-P-32b shows no pressure-broadened absorption features from Na and K,
which is interpreted by the presence of clouds or hazes in the planetary
atmosphere. This result is in agreement to previous studies on the same planet.
The presence of TiO in gas phase could be ruled out. We find a 2.8 sigma
indication of increased absorption in the line core of potassium (KI~7699 AA).
No narrow absorption features of Na and Halpha were detected. Furthermore,
tentative indications were found for a slope of increasing opacity toward blue
wavelengths from the near-IR to the near-UV with an amplitude of two scale
heights. If confirmed by follow-up observations, it can be explained by
aerosols either causing Mie scattering or causing Rayleigh scattering with an
aerosol - gas scale height ratio below unity.
