Mark,
Consider also that the 2" diagonal has a larger mirror of which only the central portion is being used. This is the best part of the mirror as far as flatness and shape. Because of this a 2" diagonal can be a better unit. Of course the quality of the coatings and mirror as well as the precision of the construction and alignment will effect the view just as much. So a good 2" is the way to go.
Consider also that the 2" diagonal has a larger mirror of which only the central portion is being used. This is the best part of the mirror as far as flatness and shape. Because of this a 2" diagonal can be a better unit. Of course the quality of the coatings and mirror as well as the precision of the construction and alignment will effect the view just as much. So a good 2" is the way to go.
[SIZE="Large"][/SIZE][COLOR="Blue"][/COLOR] Floyd Blue
Amateur Imager