  We present here new transmission spectra of the hot Jupiter HD-189733b using
the SpeX instrument on the NASA Infrared Telescope Facility. We obtained two
nights of observations where we recorded the primary transit of the planet in
the J-, H- and K-bands simultaneously, covering a spectral range from 0.94 to
2.42 {\mu}m. We used Fourier analysis and other de-trending techniques
validated previously on other datasets to clean the data. We tested the
statistical significance of our results by calculating the auto-correlation
function, and we found that, after the detrending, auto-correlative noise is
diminished at most frequencies. Additionally, we repeated our analysis on the
out-of-transit data only, showing that the residual telluric contamination is
well within the error bars. While these techniques are very efficient when
multiple nights of observations are combined together, our results prove that
even one good night of observations is enough to provide statistically
meaningful data. Our observed spectra are consistent with space-based data
recorded in the same wavelength interval by multiple instruments, indicating
that ground-based facilities are becoming a viable and complementary option to
spaceborne observatories. The best fit to the features in our data was obtained
with water vapor. Our error bars are not small enough to address the presence
of additional molecules, however by combining the information contained in
other datasets with our results, it is possible to explain all the available
observations with a modelled atmospheric spectrum containing water vapor,
methane, carbon monoxide and hazes/clouds.
