That 'halo' is most deliberate. It's an innovation of mine, it being a dynamic reflection of the collimating lens. The intensity is maximal when the Sun is shining straight down upon the sight, and reduces in intensity as the direction of sunlight swings away from this.
For the N-2A sight, with its partially enclosed reflector support, I gave the reflection texture a uniform, parallel directionally for the surface normals at the 4 corners of the texture. This means the entire reflection varies in intensity uniformly.
The GM-1 sight, being less 'enclosed, has had the texture surface normals at the four corners strategically made to be divergent. This results in a differential in texture brightness as the direction from which the Sun shines varies, simulating the effect of reflections from the curved surface of the convex lens. Observe what happens as you bank your plane, noting how the reflection dims or brightens differentially.
These reflections are doubled up, with a small vertical offset, a consequence of the thickness of the reflector plate and the fact of the reflections from each surface originating from the very nearby lens. (The reticle's image does not exhibit such a doubling because the light for it is collimated to parallelism.)
Such kind of reflections do occur in reality. Indeed, I was first inspired to devise this additional aspect from the appearance of reflections in some photos of gun sights on the web. (I've examined and saved a lot of gun sight images, starting almost a decade ago when commencing my own sight mods.)
These optical issues are the kind of things I would be aware of as an optician who has fabricated a variety of lenses and mirrors for industry and science, as well as having been an amateur astronomer and photographer for decades.
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Topic: Hawk 75 cockpit update, for 4.12 and B.A.T. (Read 3636 times)
