A “Past Master” is a Freemason who has been Worshipful Master of a lodge. Some “craft” lodges have the emblem above for the Past Master. Later “Past Master” became part of systems of additional degrees, such as the York Rite and the French Rite higher degrees (2nd order). The sun in the middle is not always part of the Past Master symbol. The fifth degree of the Ancient and Accepted Scottish Rite (“Perfect Master”) also has this symbol without the sun. In the rite of Memphis-Misraim the Compasses and Protractor with sun are the emblem of the 14th degree (“Grand Elect”).
Interestingly, the image can also be found on an image (of a tracing board) of the oldest known ‘high degree’ ritual from 1747. See here.
Duncan’s Masonic Ritual and Monitor (1866) by Malcolm C. Duncan