An alignment adjusting device for an optical focal plane assembly, which is adapted to be integrated in the optical focal plane assembly comprising a detector having a detector plane and being adapted to be mounted to an optics assembly having an optical focal plane, wherein the alignment adjusting device is adapted for allowing an alignment of the detector plane representing an image area and the optical focal plane, the alignment adjusting device comprising: - a detector support for receiving the detector; - a plurality of members (15, 13, 12, 4, 8), a first member of the plurality of the members being connected to the detector support and a second member of the plurality of the members being connected to a flange that is adapted to be connected to the optics assembly; - the first member, the second member and the remaining number of the members being pairwise moveably connected to each other by means of a number of springs and/or a number of supporting elements (5, 7), the number of springs and/or the number of supporting elements (5, 7) being adapted to enable a translational movement along axes (x, y, z) of a given coordinate system and/or a rotational movement around the axes (x, y, z), characterized in that: the remaining number of the members of the plurality of members (15, 13, 12, 4, 8) consists of: - an intermediate ring representing the second member being connected to the flange by means of detachable lock bolts; - an outer frame being firmly connected to the intermediate ring and having a substantially cylindrical shape; - an inner frame being coaxially arranged to the outer frame and having a substantially cylindrical shape; - a first flexible joint connected to the inner frame; and - a second flexible joint representing the first member. - a detector support for receiving the detector; - a plurality of members (15, 13, 12, 4, 8), a first member of the plurality of the members being connected to the detector support and a second member of the plurality of the members being connected to a flange that is adapted to be connected to the optics assembly; - the first member, the second member and the remaining number of the members being pairwise moveably connected to each other by means of a number of springs and/or a number of supporting elements (5, 7), the number of springs and/or the number of supporting elements (5, 7) being adapted to enable a translational movement along axes (x, y, z) of a given coordinate system and/or a rotational movement around the axes (x, y, z), characterized in that: the remaining number of the members of the plurality of members (15, 13, 12, 4, 8) consists of: - an intermediate ring representing the second member being connected to the flange by means of detachable lock bolts; - an outer frame being firmly connected to the intermediate ring and having a substantially cylindrical shape; - an inner frame being coaxially arranged to the outer frame and having a substantially cylindrical shape; - a first flexible joint connected to the inner frame; and - a second flexible joint representing the first member. - an intermediate ring representing the second member being connected to the flange by means of detachable lock bolts; - an outer frame being firmly connected to the intermediate ring and having a substantially cylindrical shape; - an inner frame being coaxially arranged to the outer frame and having a substantially cylindrical shape; - a first flexible joint connected to the inner frame; and - a second flexible joint representing the first member.