illumination over various horizontal arcs of visibility in addition the disclosure encompasses three modes of diffuse light projection to achieve uniform illumination over various vertical arcs of visibility due to the precision of the results obtained the optical elements provide navigation lights fully in compliance with the rigid specifications for arcs of visibility set forth in the final act of the international conference on revision of the international regulations for preventing collisions at sea 1972 and the international rules of navigation act of 1977 33 u s c 1601 and do so with particular economy application_number US 14996280 A description in the accompanying drawings fig1 through 12 are concerned with the divergence of light within selected or prescribed horizontal arcs of visibility and fig1 through 20 are concerned with the divergence of light within vertical arcs of visibility basically four devices are described each consisting of an optical element to be supplied with luminous energy from any convenient economical readily available source hereinafter referred to as a 34 lamp 34 and to emit light through a lens or filter which may be colored or clear over a precise angle of visibility thereby to facilitate athe manufacture of navigational lights fully satisfying all applicable laws and regulations the.