An astrolabe is an astronomical instrument enabling the user to identify stars and planets and their positions as well as being an aid to navigation. I have based this model on an instrument in the collection of the British Museum (1909,0617.1) dating back to 1326 - click this link for more information https://www.britishmuseum.org/collection/object/H_1909-0617-1 To learn more about the use of these instruments click this link https://en.wikipedia.org/wiki/Astrolabe I have used images for reference that are copyright of the Trustees of the British Museum and they are for non commerial use only - so I have made this model 'non-commercial use' I made the model in Zbrush and created a set of alphas in Procreate on the ipad closely following the markings on the original instrument. I used these in Substance Painter to create the etched details. This model is not really for 3d printing - the markings will not appear on the print.