ASPHERIC MIRROR WITH CONSTANT ANGULAR MAGNIFICATION .2.

Differential equations for a constant-angular-magnification aspheric-m irror surface shape are derived for a general dependence of the camera image height on the camera field angle. The explicit equations of the constant-angular-magnification mirror surface are given for some part icular values of the angular magnification. For a series of odd intege r values of the angular magnification, 10th-order polynomial approxima tions of the mirror surface are presented. The imaging performance of such a mirror with an angular magnification of 7 is analyzed and compa red with a spherical mirror. The main cause of image blur in all-sky c ameras at the edge of the field of view was found to be a strong image curvature. We show that increasing the camera-to-mirror distance and/ or stopping down the camera lens reduces the image blur.