It's on a printed backdrop behind a cafe. Normally it doesn't get seen from this angle (because the vista requires a forced perspective to work) but in "The Fall of the Night" the camera is awkwardly placed and this checkerboard ball is visible. It looks a lot like the boing ball to me!
Babylon 5 famously used Amiga products to make the cgi... so I want to believe...
Enzmann Starship. A crewed interstellar starship concept by Dr Robert Enzmann. You can learn more about the concept here https://enzmannarchive.org/ Model by @Nick_Stevens_graphics btw you should definitely check out his work. Rendered in #LightWave3d
Some Space 1999 Eagle images. I’ve recently backed a Kickstarter project to produce the definitive documentary on this iconic ship. #LightWave3D#Space1999