An off-axis aberration affecting image quality, this defect causes point sources of light, such as stars, to appear as comet-like shapes, with light increasingly trailing away from the center of the field. This distortion worsens further from the optical axis, rendering images less sharp and more diffused, particularly towards the edges of the view.
Its presence significantly impacts the resolving power of reflecting telescopes, diminishing the contrast and clarity of observed celestial objects. Historically, minimizing it has been a key objective in telescope design, driving advancements in optical configurations and corrective elements. Addressing this issue is essential for high-resolution astronomical imaging and precise scientific measurements.
