The phrase "visible with unaided eye" refers to objects or phenomena that can be seen without the assistance of any optical device. Synonyms for this phrase include "naked-eye observable," "apparent," "conspicuous," "easily observable," "plainly visible," and "unmistakable." Other phrases that convey the same meaning include "readily noticeable," "clearly discernable," and "visible without optical aid." These phrases are commonly used in various fields such as astronomy, geology, and biology where observing natural phenomena is critical. In general, the phrase "visible with unaided eye" is a simple and concise way to describe something that is easily seen without any devices or tools.