  Mini-EUSO is a UV telescope that will look downwards to the Earth's
atmosphere onboard the International Space Station. With the design of the
ultra-high energy cosmic ray fluorescence detectors belonging to the JEM-EUSO
program, it will make the first UV map of the Earth by observing atmospheric
phenomena such as transient luminous events, sprites and lightning, as well as
meteors and bioluminescence from earth. Diffused light from laser shots from
the ground, which mimic the fluorescence light emitted by Nitrogen molecules
when extensive air showers pass through the atmosphere, can be used to verify
the capability of this kind of detector to observe ultra-high energy cosmic
rays. To validate the electronics and the trigger algorithms developed for
Mini-EUSO, a scaled down version of the telescope with 1:9 of the original
focal surface and a lens of 2.5 cm diameter has been built. Tests of the
Mini-EUSO engineering model have been made in laboratory and in open sky
condition. In this paper, we report results of observations of the night sky,
which include the detection of stars, meteors, a planet and a rocket body
reflecting the sunlight. Interesting results of the observation of city lights
are also reported.
