Orion Clear aperture telescope

I came across this on telescope-service.
www.telescope-service.com/OrionUSA/refle...eflectors.html#Clant

Would be interesting if this progresses to larger sizes at better prices.

The problem is the way it needs to be made. To make the mirror, you actually need a much larger mirror and then cut a piece out of it. The centre of the large mirror now becomes a point on the edge of the small mirror directly under the mini secondary mirror. However, for apo-quality views with no central obstruction, it's certainly worth considering.

I wonder is there an optical catch in this system besides the cost.
Maybe its the way of the future once someone figures out how to make optical surfaces cheaply. !

Those off-center optics are an expensive way of gaining no benefit.

The central obstruction of a reflector has almost no deleterious effect on optical performance.

If you subtract the diameter of the central obstruction from the diameter of the primary you get the same optical performance (i.e. contrast on planets) as an an equivalent unobstructed refractor.But without the chromatic abberation.

The central obstruction never fazed the HST.

Peter.

ok, lets look at the example of my 12" SCT, the central mirror is about 4 inches, so by your logic this leaves me with an 8 " refractor ?? nope! it doesn't work that way! The bigger the central mirror the worse the image will be.
Ever hear of Strehl ratio?, I suggest you go look it up and see how differing sizes of the central obstruction in combination with the accuracy of the mirrors combine to seriously reduce the resolution of the scope.

The HST (when fixed) has optics well beyond that of "diffraction limited". Its imaging capability would be even better if it didn't need a secondary mirror.

Your obstructed 12" SCT will show about the same CONTRAST in Jupiter's clouds as an 8" refractor.

The 12" will,of course, show a much BRIGHTER image.

Peter.