Binoviewer comparison page

This table below is a direct ray trace of how a particular clear aperture and optical path will interact with a set of eyepieces. In the columns below it is broken down into three different f/ratios. These f/ratios cover many important applications and represent a best case scenario to a worst case scenario. F/11.5 is a typical f/ratio for an SCT when using a binoviewer. F/7 is using the binoviewer a Refractor or SCT with a focal length reducer (FLR) in place giving roughly a 40% reduction off of the f/11.5. F/5.2 would represent a worst case scenario when a telescope such as a Dob is used with an optical corrector.

The Figures below are the Full optical path of the binoviewer considered. EX: A 20mm plossl in the scopes focuser in contrast to the eyepiece holder of the binoviewer. The Optical path figures below are the difference in mm.

Bottom Clear Aperture	Total Optical Path	F/11.5 Fully Illuminated spot area and mm's Squared	F/7 Fully Illuminated spot area and mm's Squared	F/5.2 Fully Illuminated spot area and mm's Squared
45mm Elite	184mm	29mm. 660.2	22mm 383	12mm 113
40mm VP40	150mm	25mm 490.6	20mm 314	12mm 113
28mm	114mm	16.5mm 213.7	12mm 113	5.5mm 23.7
26mm	115mm	16mm 200.9	8mm 50	4mm 12.56
25mm BN25	100mm	16.5mm 213.7	12mm 113	5.3mm 22
22mm	115mm	11.5mm 103.8	5.5mm 23.7	0.0mm 0

Newtonian Diagonal Analysis

by Mel Bartels