UniPiHAB 04 was our first nighttime flight. We flew a scientific payload, the MINLU stratospheric gondola developed by the Dept. of Industrial Engineering & CISAS “G. Colombo” of theUniversity of Padua. MINLU includes a number of optical instruments dedicated to the measurement of light pollution in the nocturnal sky. The mission was a success, both scientifically and operationally. We learned a lot on the effects of sun heating (or lack thereof) on balloon dynamics.