be accessible and pupil masks could be put into it, to allow for aperture synthesis experiments and simulate telescope arrays such as the ESO VLTI (European Southern Observatory Very Large Telescope in the Interferometric mode) or others. This speckle camera thus provides appropriate experimental tools for the investigation of image restoration techniques with the optical telescope interferometric networks that are currently being built and operated around the world (CHARA, COAST, GI3T, IOTA, NPOI, PTI, SUSI, etc, see [*f.i.*]{} [*Astronomical Interferometry,*]{} Proceedings of SPIE, Vol. 3350, Kona, 20-28/03/98)

In the following we present an overview of PISCO and its optical concept (§2). Then we introduce the various operative modes and illustrate them with observational results (§3). The detectors that have been used with PISCO are presented in §4. In §5, we discuss the current performances of the instrument in relation with the physical limitations of the speckle techniques and the image restoration methods. In §6 we briefly describe the on-going scientific programs which use PISCO, and conclude about the use of a speckle camera in the current context of new high angular resolution techniques.

[**2. The PISCO speckle camera**]{}

10000 Compared to other speckle cameras (Blazit [*et al.*]{}, 1977, Breckinridge [*et 