I planned to do this design so long, but for the sphere part i needed a bit help and time. Now is done! This design is based on both Star Wars Battlefront game V-150 cannons from Hoth maps. This Model is high detailed, except the buttom part (what is mostly not seenable). For FDM Printer the smallest print where the details are seenable is 30% scale, with a bit horizontal expansion, then the sphere part diameter is almost 13cm and the cannon is almost 5cm heigh.I made a hole in the cannon, so if someone wants to put some light in it, then this makes it easier. This idea came from Boylei Hobby Time - DEATH STAR II + LED LASER TUTORIAL.
I made 3 version of result of sphere and cannon
Print the cannon part 1% less scale to fit into the sphere.