Re: First light: Williams Optics binoviewers
Posted: Tue Apr 25, 2023 1:53 pm
What matters is that the aspect ratio of the box defined by theLady Fraktor wrote: ↑Tue Apr 25, 2023 4:05 amI will admit that I am a bit confused but I think it is mixing terms that do not apply.SkyHiker wrote: ↑Mon Apr 24, 2023 7:35 pm Clearly, if the BV tube becomes shorter and/or thicker (its focal ratio as I defined it gets smaller), the vignetting will be less and eventually will go away. If the BV focal ratio is exactly that of the OTA the central light bundle will be unobstructed but the outer ones are still partially obstructed. Hope this explains the thought that I wanted to get across.
bv.jpg
The BVs have no focal ratio but they have a focal length, so thef/ r will not match between BVs & telescope.
It also effectively increases the focal length of the objective so in the picture, imagine the objective is further to the right corresponding with the multiplication factor caused by Barlow; in that case the central light cone is narrower and there is more clearance at theLady Fraktor wrote: ↑Tue Apr 25, 2023 4:05 am Using the OCA just negates the f/l of the BVs so focus can be achieved.
Not quite, the eyepiece represented as a box had a height (corresponding with the field stop size) that was less than that of theLady Fraktor wrote: ↑Tue Apr 25, 2023 4:05 am The picture is pretty much what is happening if you exceed the clear aperture of 22 mm