Line below Earth represents distance of Earth's centre from the system barycentre. Line below the Moon represents perigee and apogee with the moon at the semi‐major axis position. Moon shown with correct side facing earth, but without any pretty shading. The below information refers to the original version of this file, which was twice the size of the current version (i.e. it's now 14.25 km/px). Sorry but Photoshop wasn't saving them very well, so I had to switch to GraphicConverter, which is limited to 16,000 pixels across. Earth-Moon system at a scale of 7.1224 km/px (0.140402 px/km)

• Earth polar diameter = 12,713.5 km (893px) ⇒ 7.1224 km/px
• Moon equatorial diameter = 3,476.2 km (244px)
• Lunar apogee = 405696 km (28480px)
• Lunar semi‐major axis = 384400 km (26985px)
• Lunar perigee = 363104 km (25490px)
• System barycenter = 4700 km (330px) Scale chosen because Photoshop only supports images 30,000 pixel in width, and scaling the Earth by 50% just about fits with this, all other measurements derived from there.