720x!!!

[Stargazer_00]

What about ring stops. So something like a 3" thick ring with an outer diameter of 14" and an internal diameter of 8". this would allow a smaller aperture but keep the vanes and central obstruction in the field. Would allow for larger apertures than a single quadrant would allow. I would have to consider the ratio of aperture to central OBS of course but would this work?

[John]

Smaller aperture with a proportionately larger central obstruction % isn't a good combination for good resolution / contrast. I think the benefits come from unobstructed aperture. 

[AlexB67]

The aperture mask trick is another one of those areas that has hugely variable opinions as to what they bring in practice , I recall reading about them in some detail but it turns out to be very much one of those topics of

Some say ...  etc. etc.

what they actually bring in practical terms when reviewed by astronomers out in the field varies a lot. Theoretically a lot of it makes sense and is hard to argue with.

I never tried it so far in my 10 inch and I do have that cap with a hole, so could easily try with that for fun.

I do recall reading a detailed study showing that multiple holes  aperture masks can work also, two or four holes between the vanes unobstructed, but simulations showed that placing them is important and how they affect the interference pattern, clearly it will affect diffraction patterns, that is if I recall the details of said article correctly.

I'll see if I can dig it out said article and link it, I think it was actually the work of a whole PhD thesis, but the first chapters or so gave a thorough introduction  and many simulation studies showing the resulting diffraction patterns and the consequences that brings.