A method for opening a dome for the protection of a device to be protected, fitted in a part described as fixed, in which, in the initial position before opening, a generally plane interface separates the dome from the fixed part, is provided. The method includes connecting the dome to the fixed part by at least two independent double-link connections that are movable in rotation between the dome and the fixed part. The links in a single connection being fitted in common to the dome and to the fixed part to form overall a pantograph in the shape of an isosceles trapezium which, during opening, opens out by pivoting until maximum opening is achieved, so that the dome moves away from the fixed part via a combination of movements in translation and in rotation.