Astrolabe

This was inspired by a TED video by Tom Wujec. See it here: http://www.ted.com/talks/lang/eng/tom_wujec_demos_the_13th_century_astrolabe.html I spent some time drawing this in Corel and used a variety of sources for copying the lines. The electric astrolabe from here; http://www.astrolabes.org/electric.htm was an excellent source and star fields can be printed for any location. Thanks to James Morrison for that. Another good source is from Daniel Rislove here: http://www.uwsp.edu/physastr/rislove/astrolabe/resource.htm You can print a paper version to test it. You can download a program for creating sundials and astrolabes ( they cost ) here: http://pagesperso-orange.fr/blateyron/sundials/shadowspro/

Since I currently live in Peru I was interested in creating an Astrolabe for Southern hemispheres, they work in reverse so I needed to create a different outer ring and rete. I have included parts for both hemispheres. The instrument is probably not very accurate as I used images as a starting point then drew over them using the line tool. It was easy to create the outer ring division in Corel accurately but the hemisphere lines in the centre were more difficult. If anyone knows a way of doing these mathematically for any longitude please let me know. Next step is to have a go at making this with a bronze plate using our Roland EGX 350.