To Calculate actual Vertical offset within vertical keystone spec

           

tan-1(The difference between height of the top of screen and the height of the projector divided by the distance from screen to projector)

           

Example:

           

Top of screen= 79”

           

PJ height is = 96”

           

96”-79” = 17”  

           

Difference is 17”

           

Distance from screen to PJ( which is given by the image size and throw distance chart) = 135”

           

tan-1 (17/135) = 7.2 degrees

           

Correctable with vertical keystone adjustment ( Vertical Keystone correction is 15 degrees max)