Animation showing Earth's orbit. Then the type of planet the Roman Space Telescope will be able to directly observe: roughly Neptune size in a 1.6AU or greater orbit. And, finally, the type of planet at the current limit of direct observation: Jupiter-size or larger and 40AU from its host star.
Animation showing the locations of the Earth-sun Lagrange points, places where gravitational effects create stable locations that a satellite can remain it with minimal effort. The Roman Space Telescope will orbit at L2, about a million miles away from Earth.