From the designer and telescope maker R.F. Royce…
“From this optician's viewpoint a reasonable standard for telescopic objectives of high-quality would be those producing a Strehl ratio from preferably .96 (1/9 wave, P-V) with .97 (1/10 wave, P-V) as representing the best that is reasonably attainable.
.90 Strehl is around 1/5 wave or a touch better and according to a Royce chart is “below” what is considered “even good” for a high-quality optic.
Consider that it has been well documented that high quality Tak and AP 6 and 7-inch refractors have delivered better planetary performance than much larger 9.25, 11 and 14” SCTs, which of course have much larger apertures but are also less well figured.
Consider also this statement (HERE is a link) from Carl Zambuto about optical quality and contrast. Contrast is important for planetary observing.
From Roland Christen…
“Compare the roughness of the wavefront of the different types of scopes. The effect of roughness is to scatter light from the Airy disc into the diffraction rings. In the case of planetary viewing, it creates a thin veil of light that lowers contrast.”
Consider that Roland Christen, in his article on telescopes for planetary observing, when talking about refractors for planetary performance compares smaller 7 to 9” apo refractors to larger 8 to 12” achromatic refractors.
Considering the above, I think a reasonable conclusion “in your example” is that for planetary performance and “observing the finest details and subtle tonality differences ” the higher optical quality telescope will have better contrast and would deliver more.
Edited by bobhen, 25 January 2021 - 07:59 AM.