Radian or good Orthoscopic?

For planetary contrast, which is better a Radian or a good orthoscopic. I'd be interested in hearing from anyone that has tested both. Thanks

I think it depends somewhat on the scope, but I preferred an 8mm Radian to a 7mm Tak ortho in my 10" f/5 Newt. But then again, I prefered the 7mm Pentax XL to the 8mm Radian on that scope also (though not on contrast). With Abbe orthos in faster scopes, it's critical to keep the planet or feature (in lunar viewing) centered. Otherwise, off-axis astigmatism in the Abbe design will degrade the image. Even in a Newt with its coma, I believe this astigmatism will quickly dominate other abberations. If you are using a fast scope and for any reason regard centering a difficult or annoying requirement, then a Radian is clearly preferable, IMO. The best performance is to be had in the center of the view, but the Radian is more forgiving in fast scopes if you look off-axis a bit. In slow scopes, I think most people would prefer the Abbe ortho. Many scopes are somewhere in-between what would be regarded a fast or slow. Can't help you there. Might as well try both and decide for yourself.
--
Mike

If it is of any significance, my older styled University Optics 16mm Konig on my 2x Ultima barlow equalled an 8mm Radian on Jupiter in my 6" ED refractor last weekend. I almost thought I saw a reflection in the Radian that was not there in the Konig, perhaps due to the Radian's concave eye lens vx. the Konig's convex one. Contrast, sharpness, sky blackness around the planet, all the same.