Double Stars
Close double stars can show the performance of a telescope at their highest resolution. The examples below show the effects of  Lower Spherical aberration
(0, 1/5, 1/4, 1/3, 1/2 Wave P-V) and obstruction (0 , 20, 30, 40%) on a 1 arcsecond separated double star as seen through a 6” telescope.

0bstruction free

20% obstructed

30%obstructed

40%obstructed

1/5 wave LSA (PV)

1/4 wave LSA (PV)

1/3 wave LSA (PV)

1/2 wave LSA (PV)