Hello!! It's Joseph

 there is discussion from Cloudynights For lunar/planet viewing, I would choose the C11. In most locations, the usual mediocre or poor seeing compromises scopes above 6-inches or so. Combine the seeing with objects that are not always positioned perfectly high in the sky and both of these scopes will be affected. The Mak might produce a very slightly sharper image compared to the C11. The C11 will produce a brighter image and will have more resolving power when the conditions are good. The C11 will be better for deep-sky viewing and imaging. There is a comparison here on CN between a high-end, 9-inch Mak and a C11. The C11 came close in most observations so it should deliver better performance against a commercially produced 7-inch Mak. (meaning C8 is inferior to a Mak7?)  Things to consider for best performance: Collimation, Thermal Management, Dew/light shield (some of the best nights are moisture heavy), A good aftermarket focuser, a good aftermarket high-end diagonal, good...

  The optical design is based on gregory-maksutov or spot maksutov telescope, and often called as CAT ( catadioptric) lens which is a combination of mirrors and refractive lens most of these lens are manual focus. The aperture is fixed. It is virtually free ( marketing bluff beware) of chromatic aberration, coma, and off-axis aberrations. However, due to central obstruction of secondary mirror, contrast is normally lower. However, lateral color aberration ( different image size for different colors) still exist, except on the Zeiss mirotar, which use dual corrector plates The overall image quality depends mainly on the secondary mirror aberrations. So in lower priced models, if the secondary mirror is a separate element, it has more room for improvement. Exposure: The secondary mirror blocks about 1/3 of the area of the lens aperture. This in itself would result in the loss of about 2/3 stop in effective lens speed (i.e. a T-stop that was 2/3 stop slower than the f-stop). The actu...