Quote:and yet the amount of light delivered to the exit pupil is equal.
So this cabbie says: "Know who I had in this cab last week? Bertrand Russell! Wisest man in the Western World. And I says to him 'Bertie, what's it all about?' And do you know, he couldn't tell me..." Kenneth Williams
Quote:Quote:and yet the amount of light delivered to the exit pupil is equal.
Even after accounting for the difference in AFoV? It's a bit perilous to speak of the exit pupil as a whole. I take it you mean that the smaller aperture may deliver more light at a given apparent field angle, primarily because the corresponding light cones are less obstructed by limited-size prisms but also possibly due in some measure to transmission differences. If this happens "enough" (I believe you described a Riemann Sum approximation to a certain integral), then the smaller aperture may indeed deliver an overall brighter view.
Quote: Here's a method I use for measuring effective aperture. It is also used to determine the percent of the objective that provides 100% illumination. It's really quite simple. You can refer to the post (EdZ 02/27/09 06:07 PM) in this thread to read the description of what can be measured or just follow further down to the picture presentation to see how its done.
Measuring Effective Aperture with a Collimating Laser Target.
Quote: Any observing reports with the WO and the taks edz?
Quote:EdZ...Among other nitty gritties--I hope you compare the current price for each of these models.
Quote:I guess the picture isn't that much help to estimate things at a glance after all.
So it is possible to figure out what the actual size of the "hat" is, and how much deeper you can see? Also I'm not sure how AFOV figures into this.
Quote: . . . but the chances of getting one are buckleys. . .
Quote: The advantage of a better illumination profile is to show just as much, or nearly, away from the center as in the center. That's a nice feature for large objects and open clusters, cruising the Milky Way, etc.
Milton Wilcox R.I.P
Quote: measuring illumination, but if it was done with on-axis rays at various points on the objective, then he is measuring illumination at the center of the field.
Quote: The larger exit pupil for on-axis illumination would not necessarily be a brighter one if the light coming from the edges of the objective is cut down by a large percentage because the prisms are inefficient at the angle of incidence.
Quote: the statement 83% illuminated to 100% should mean the image is 100% illuminated from off-axis light that enters at 83% out on the aperture