12inch Dobsonian Truss Telescope - LEGACY

grabcad

This is a continuation of my previous project to design and build a 10 inch Dobsonian truss telescope.I managed to acquire a 12-inch (300mm) mirror with a focal length of about f6.This size of mirror makes the overall telescope shorter than the previous 10-inch f9.8 design and therefore far easier to handle and use.The design is, however, modular meaning that I can change the mirror cell and the length of the truss arms to accommodate different mirror sizes and focal lengths.The Three rings that make up the telescope itself are carbonfibre with a 3mm honeycomb core. Everything else pretty much is aluminium in the 5000 or 6000 series.The supporting side panels are made using a Welded U-channel aluminium frame skinned in 1.5mm aluminium sheet which is Resin Bonded and riveted to the U-channel.The base itself is completely constructed of sheet metal using resin bonding and riveting.There are reinforcing ribs in the core of the Base which are bent into an S shape to provide stiffness between the two sides of the base.The design also includes a telescope GOTO system that is completely open-source, search for "OnStep Telescope" on google if you want to know more.I'm using 400 Step-per-Rev NEMA-17 Stepper motors with a 100:1 planetary drive and a final Timing belt reduction ratio of 2.2:1This is still a big work in progress so please feel free to ask questions or leave comments.