Relationship between axial displacement error and defocus. RoC, radius of curvature.|@|~(^,^)~|@|Relationship between wavefront focus shift ΔR and wavefront sag change Δs. RoC, radius of curvature.|@|~(^,^)~|@|Surface defocus errors (a) when the axial displacement error is 1 mm and (b) when the axial displacement error changes for different R/#.|@|~(^,^)~|@|Configuration of segmented mirror measurement using a Fizeau interferometer.|@|~(^,^)~|@|(a) Experimental setup using a Fizeau interferometer. (b) Used data (Coef 3, surface defocus error) from the Fizeau interferometer.|@|~(^,^)~|@|Fizeau interferometer surface defocus error obtained with increasing the axial displacement error (a) at 1 mm interval and (b) at 2 mm interval.

2023;34:22~30 https://doi.org/10.3807/KJOP.2023.34.1.022