The antonyms for the phrase "be within view" would be "out of sight" or "invisible." When something is out of sight, it means that it cannot be seen or observed. It could be hidden, obstructed, or too far away to be within the range of vision. Alternatively, something could be invisible, which means that it cannot be perceived by the eye at all. It could be due to its size, transparency, or the absence of light. Both of these antonyms stand in stark contrast to the phrase "be within view," which indicates that something is present and visually accessible.