For Husserl, the perception of objects is necessarily inadequate due to what he and Merleau-Ponty describe as the “horizon.” This refers to the hiddenness of any object of perception due to a singular human vantage point and finitude. Any perception of an object can only be of a determined aspect or dimension of an object. If I perceive a table, the representational content given by the sensations will always contain an unknown. I cannot, even totaling up all the possible facts of an object and possible angles, perceive every aspect or relation within the object, as I always perceive from some determinate, singular perspective or vantage point.
It would, in fact, require omniscience to perceive an object in its totality. This being the case, Husserl speaks of the objects horizon, which is in fact ever-present and insurmountable. This is the reason, then why perception of things is always necessarily inadequate. That requirement of omniscience is what Husserl means when he speaks of adequate perception as an ideal: It is something we cannot in actuality achieve.