Sheldon Coopers Galaxy Shirt

I haven't yet found the location of this shirt but it would appear to be depicting an overhead view of a spiral galaxy (I'm pretty smart, huh?). There also looks to be a small dot on one of the spiral arms, which I'm assuming is pointing out a planet or a solar system. Judging by the position of the dot, I'm also suspecting that this is meant to be a representation of our own Milky Way galaxy with the dot pointing out our little position within it. Whether I'm right or wrong, I still don't know where to get my hands on this dang thing though.

Featured in The Big Bang Theory episodes

S10 E13: "The Romance Recalibration"
S10 E19: "The Collaboration Fluctuation"
S11 E05: "The Collaboration Contamination"
S11 E12: "The Matrimonial Metric"
S12 E01: "The Conjugal Configuration"
S12 E08: "The Consummation Deviation"
S12 E19: "The Inspiration Deprivation"
S12 E23: "The Change Constant"