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My experience using both a quality 103mm APO and an NA140SS in rural dark skies is quite different. The 140 collects twice the light of the 103 and this delivers unquestionable far superior images and detail across all deep sky objects. The 140 is unquestionably my first choice for all double star, globular and open clusters, nebula, planetary nebula and galaxies etc observing at all magnifications and exit pupil sizes.
Looking through my observing logs, my best views of Saturn and it's six accessible moons have been through the 140. Views of Jupiter are on a par but the comparisons between observations in my logs seem to be more dependent on the seeing conditions. But again my first choice is the 140 as it resolves the moons as small disks. Jupiter shows a small faint blue fringe close to the limb but it is not obtrusive and I have never seen any sign of this bleeding onto the plante's disc.
The images of the moon through the 140 have a very faint blue wash across them. This does not affect image sharpness at low magnification up to about 70X. Again the greater aperture yields more detail at these magnifications. However, at high magnifications there is a definite loss of sharpness in the image. A Baadar Fringe Killer filter cleans up the image sufficiently to rate it as satisfactory. The faint yellow cast produced disappears from view after a few minutes observing. Having said this, the 103 produces a far superior image at medium to high magnifications and is my preferred scope for all Luna observing.
Another thing going for the 140 is it's relatively compact size and lower than expected overall weight. It is very manageable.
I don't see any evidence that the turnover in these scopes is any different to the average across all good quality scopes.
Hope this hands on experience helps.
Cheers
Steve.
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