Visibility Function--Disk -- from Eric Weisstein's World of Physics

V v

Visibility Function--Disk

Is given by the visibility function: ellipse with a = b,

where

and D is the baseline distance. The nth zero in a plot of visibility amplitude vs. baseline distance ( vs. ) there occur when

where denotes the nth zero of the Bessel function Eric Weisstein's World of Math. The angular diameter of the disk is then

Since the first few zeros of are 3.8317, 7.0156, 10.1735, and 13.3237, the diameters calculated from the first few zeros are