We present the stellar populations properties of the interacting spiral NGC 5719, which is known to host two cospatial counter-rotating stellar discs.

A large fraction of otherwise normal galaxies shows weak nuclear activity. One of the signatures of the low-luminosity active galactic nuclei (LLAGNs) is the ultraviolet variability which was serendipitously discovered in the center of some low-ionization nuclear emission-line region (LINER) galaxies (see Ho 2008 for a review).

The mid infrared emission of early type galaxies traces the presence of intermediate age stellar populations as well as even tiny amounts of ongoing star formation. Here we discuss high S/N Spitzer IRS spectra of a sample of Virgo early type galaxies, with particular reference to NGC 4435. We show that, by combining mid infrared spectroscopic observations with existing broad band fluxes, it is possible to obtain a very clean picture of the nuclear activity in this galaxy.

We present UV data of a small sample of shell galaxies. For the majority of them (namely, NGC 2865 and NGC 7135), the NUV matches the optical emission, while the FUV is present in the innermost regions alone.

The kinematics of galaxies belonging to the Hickson compact group HCG67 are investigated. The latter consists of four galaxies, three of which (a, c, d) are embedded in a common envelope. The fourth galaxy (b) is a spiral that is detected both in radio and in IR wave-bands. Our observations show that the three galaxies in apparent interaction are probably caught during an ongoing merger process.

The small orbiting observatory MOUSE is described in its essential features. Insights in the optical solution (a 2 mirrors 3 reflections telescope using pure hyperbolical surfaces, no aspherics) are given which fit such type of optical layout to scientific requirements. An in-flight recentering of the photons collected by a solar-blind photon counter device will allow for an equivalent angular resolution of 2–3 arcsec over a field-of-view exceeding one square degree. The capabilities of the proposed satellite (imaging, low resolution grisms, polarizers) are described. The choice of the selected sky areas (the two Galactic Poles, the galactic equator and some Bulge Windows) is justified in terms of forefront astrophysical scientific objectives requiring imaging in UV over large fields. The science comprises UV analysis of a complete sample of QSOs, stellar population in galaxies, White Dwarfs, Globular and Open Clusters and OB Associations. In addition a plan for the early UV detection of Supernova events is described.