This astrolabe was developed by the Portuguese in the 15th Century (much later than the "planispheric" astrolabe). It was designed to be used for both sun and star observations, and as a practical working model is the simplest of all to use. The construction of this astrolabe kit, is precision die-cut in metallic surfaced cardboard. It is easy to assemble and comes with an illustrated brochure outlining its history at sea. SW 0.7 lbs.