The digital projector, based on LSS projection system, is equipped with a special optical system able to transform the image produced by a planetarium software and display it on a curved surface. This is possible by using a fisheye camera lens that allows a stereographic 180 degrees projection, with no distortion, cuts or defects in the image. It consists of two separate elements: a full-HD video projector and an optical unit, made of a 50mm camera lens, a telescope diagonal and a fisheye lens, all assembled by means of a fully adjustable mount with six degrees of freedom. The projector is small in size and easy to carry, and can be easily reproduced. The quality and stability of the projection has been tested in an inflatable dome, and it can be used in a portable planetarium, aiming to the teaching and communication of Science and Astronomy.