The moons of Jupiter and Saturn

Mars can be a frustrating planet to observe. It is small and distant, and the local dust storms can mask most of the surface features, leaving only a subtile hint of detail in most small scopes. But, even so, you can begin to see the disk of the planet with even a pair of astronomical binoculars; which is to say at 20-30x.

Understandably, the Jovian system is about 3 times as far from us, and even its largest moons are but 2/3 the size of Mars. But, 30x300%x3/2=135x, and even on a calm clear day when I can crank my 8 and 10 inch scopes up to around 500x the moons resolve to mere star-like points of light. Is it possible to resolve the moons around these systems a bit more clearly; and, if so, what does it actually take to get to resolve to at least a nice round disk for these objects?

Enrique Barrio said:

Mars can be a frustrating planet to observe. It is small and distant, and the local dust storms can mask most of the surface features, leaving only a subtile hint of detail in most small scopes. But, even so, you can begin to see the disk of the planet with even a pair of astronomical binoculars; which is to say at 20-30x.

Understandably, the Jovian system is about 3 times as far from us, and even its largest moons are but 2/3 the size of Mars. But, 30x300%x3/2=135x, and even on a calm clear day when I can crank my 8 and 10 inch scopes up to around 500x the moons resolve to mere star-like points of light. Is it possible to resolve the moons around these systems a bit more clearly; and, if so, what does it actually take to get to resolve to at least a nice round disk for these objects?

Hmmm...
It seems to me they should reveal as disc's already. Cooling, collimation, atmospheric seeing and the eye's own astigmatism are things to take countermeasures for. But Jove's largest should show diameter, albeit small.

I can resolve discs on the Jovian Moons and even on the largest ones for Saturn with my 14.5" Starmaster and the 10" Astrosky. In fact I have observed 9 moons around Saturn in one evening.
I would thing that you are dealing with unsteady seeing or you are not looking at the largest moons. You should be able to resolve a disk on a fine night, without using anywhere near 400x.