Very general symbol. It appears on many tracing boards (“craft” or otherwise), on aprons, in lodge rooms. Usually on the opposite side there is a moon.
In A. & A. R. The intermediate Degrees 19º – 29º A.C.F. Jackson (1982), when talking about a 28th degree Ancient and Accepted Scottish Rite tracing board, the sun is described as: “The Sun represents the unity of the Supreme Being”.
Also, it can be the emblem of the Senior Deacon.
Top: Duncan’s Masonic Ritual and Monitor (1866) by Malcolm C. Duncan
Bottom: general officer jewel