Jim, I can't comment on the William Optics bino viewer specifically (I have the Orion budget model, works well), but I found that there isn't enough "in" travel on the ED refractors to use a bino-viewer with a star diagonal. Only when used straight-through is there enough travel to reach focus- and that just doesn't work for anything much higher than the horizon. You can use the included Barlow, in which case you can reach focus, at the expense of double the magnification. You can get around that by getting a pair of eyepieces of twice the focal length, and this works to a point, but you'll eventually hit a wall as to how low of a magnification you can get. Most Newtonians don't have the focus travel needed, as well. Generally the bino-viewers don't play nice with low-power, wide-field views, or very dim objects, (meaning small apertures) from my experience. Besides the lack of througput with small apertures, a bino-viewer can make balancing a small scope a real chore also. The Schmidt-Cassegrain telescope is really the perfect choice to mate with a bino-viewer. That said, I've always been impressed with the quality, fit, and finish of the William Optics enhanced 2" diagonal I own, so I would expect similar quality on their other products. On Wed, May 6, 2009 at 5:25 AM, jim Gibson <jimgibson0@gmail.com> wrote:
Does anyone know anything about the William Optic Binoviewers; good, bad? http://www.williamoptics.com/accessories/binoviewer_features.php