The effect is proportional to mass and it takes a big galaxy to see it. A big galaxy has typically a mass of 10$^11$ sonar masses so about 3x10$^17$ Earth masses. The angle of deflection is incredibly small for a planet.

The effect is proportional to mass and it takes a big galaxy to see it. A big galaxy has typically a mass of $10^{11} $ solar masses so about $3\cdot10^{17} $ Earth masses. The angle of deflection is incredibly small for a planet.