What was the optical effect achieved by Galileo that was an improvement over the initial Dutch models?

Answer

Producing an upright image

A crucial innovation by Galileo was correctly aligning the objective and eyepiece to produce an upright image, correcting the inverted image common in the initial simple spyglasses.

What was the optical effect achieved by Galileo that was an improvement over the initial Dutch models?
Galileo GalileitelescopeAstronomerinstrumentOptic