The above plot gives an indication of the expected sky-plane uncertainty of the specified object at the specified date and time.
The uncertainty is shown as offsets (in seconds of arc) in both right ascension and declination from the nominal solution propagated at the same time.
By definition, the nominal solution has zero offset in both right ascension and declination.
The locations of the object according to other predictions (variant orbits computed from the same initial observations, but making different assumptions about each orbit) are shown by the colored dots at the appropriate offsets. If a lot of these predictions cover only a small amount of sky, you may see a solid area of color, rather than the individual dots.
The extent of the dots and their density on the sky-plane should enable the observer to make a reasonable judgement as to whether or not the object is suitable for observing with their setup.