APM100 SD/BT-100XL-SD or IBIS/APM 120 MM acrho?

[Fedele]

HI

For the high magnifications on the planets, I have both the Mewlon 180c and a FC100DL.
Even in the turret, with both I realized I was lacking in large fields and DSOs.
So I was thinking to a large binocular.
For visual use within 60/100 x for large fields and DSOs:
1) how much is an achromatic 120 mm superior to a 100SD?
2) how much does the better contrast and definition of a 100 SD compensate for the larger diameter of a 120 ACRO?
3) Would a 100SD be close to the FC100DL in diameter? would I gain from this? and in what?

4) if i buy the 120 mm for the less cost and for the large diameter, how guaranteed would the WAu effect on DSO be? I usually love pure images of aberrations. Would the greater huge collection of light and the WAu overshadow them? (I am not referring to the chromatism which for me is the least of the problems)

Thank you