This is the sun insignia that has been painted in the first floor ceiling in the Golden Oaks Library. It looks somewhat different here, because normally we see it from angle and squished by the perspective. This is how I believe it would look if you stood directly under it and looked up. If you don’t believe me, open a PNG version of this in Paint.NET and use the layer rotation tool to rotate it in 3D. You’ll see how the perspective transformation makes it look almost identical to what you see in-show.
 
I’ve intentionally made everything look wobbly, and shifted things around, to make this look less computer-generated and give it some “hand-painted” look. As if whoever painted it didn’t measure things precisely. I might have overdone this, though.
 
I don’t think anyone has vectored this before. I checked several vector galleries on DA and searched Derpi, but I didn’t find matches. I guess I’m the only one who has ever paid any real attention to it :-)