I am finalizing an Orrery that used Arduino to move planets into their respective orbital position based on the year and month from a users input. I am looking for a table or database that has the location of each planet as represented in a concentric plane. For example January 2018, Earth was 9.81° from 0 (arbitrary I know, got to start somewhere).
Right now I am using an extremely crude formula to calculate the planets location angle based on the orbital period and a fixed date (Jan 2018). Of course this will result in gross errors when extrapolating out to dates more than a few years forward or backwards (orbits are elliptical). What I would like to do, is have a table with each planets location based on January of their respective year. I will program the system to lookup the value for each planet and move them to their respective position. Now I imagine the mathematics for producing this is WELL outside of my expertise and mathematical prowess.