Just to throw a spanner in the works here
. If you are using a ToUcam with 640 x 480 pixel chip and 5.6 micron pixels the "magnification" will be higher than another camera using a 640x480 pixel chip with 7.6 micron pixels by an approximate factor of 7.4/5.6 = 1.3x ie the larger pixel chip will be reduced by about .75x
Ie. 600mm scope using toUcam = approx 100x. 600mm scope using larger pixels = approx 75x