resolution circles

Resolution circles are visual tools used in astronomy to assess a telescope’s ability to distinguish two close objects as separate. Imagine two points in the sky that are very near each other; the resolution circle represents the smallest distance between them where they still appear as two distinct objects. When the two objects' images fit within the resolution circles without merging, the telescope can resolve them clearly. This concept helps astronomers determine the clarity of their instruments and whether they can see fine details or separate nearby stars and features effectively.