A parallax error occur when.?

A parallax error occurs when the position of an object appears to shift when viewed from different angles. This can happen when using instruments such as microscopes, telescopes, or cameras, where the observer's viewpoint is not aligned with the object being viewed. This can lead to inaccuracies in measurements or observations.

A parallax error occurs when the observer's line of sight is not perpendicular to the object being observed, resulting in an incorrect measurement of the object's position or distance. This error commonly occurs when measuring the direction or distance of a celestial body from different locations on Earth's surface, or when measuring the distance to nearby objects using instruments like a sextant or a rangefinder.