Diffraction Spikes, a Fifth Observable for Gimbal?

[Mick West]

On the left here we have the illustration of one of the "four observables" I listed in my video analysis - i.e. the rotation of the light patterns in the background.

But I wonder if perhaps there's something that deserves more focus, the rotation of the diffraction spikes. In particular the spike on "top" of the Gimbal shape, but also some more subtle similar spikes. I'd not really talked about this much, as it felt a little subjective. But staring at it more now, it seems like there's a very distinct pattern of light and dark within the "aura" (the white-ish glow).

In particular there seems to be a broad slightly dark region on the right.

To make it easier to see I increased the video speed to 4x, and rendered it at 60fps. This means it's displaying every other frame, and twice at fast at 60fps, which make the motion a lot smoother. The contrast has not been adjusted, and I took the video from a Prores 444 export of the original WMV, so the pixels should be identical.

Can you see what I'm talking about?

Here's it at different speeds:

Spoiler: visually distracting

and

 

[JMartJr]

Can you see what I'm talking about?

Yes, for me it is easier to see in the first of the spoilered vids. Or for that matter in the vid that opens your post.

 

[AmberRobot]

Is there reason to believe that this optical system would produce diffraction spikes? What are you supposing the pupil shape is?

What I don't understand when looking at this image is why there is some light areas surrounding the dark core.

This video just seems significantly lower quality than others are shown to rebut your opinion that it's engine glare. Why is this quality so low? Out of focus? High detector noise? Gain too high?

 

[Mick West]

Is there reason to believe that this optical system would produce diffraction spikes? What are you supposing the pupil shape is?

Yes, because we see them in FLIR1:

What I don't understand when looking at this image is why there is some light areas surrounding the dark core.

That's an image contrast enhancement. See:

Source: https://www.youtube.com/watch?v=r119JWI04Ls

This video just seems significantly lower quality than others are shown to rebut your opinion that it's engine glare. Why is this quality so low? Out of focus? High detector noise? Gain too high?

Possibly all of the above. But also it's 2x digital zoom, which increases the noise (we see this in FLIR1, compare noise in 1x and 2x)

 

[AmberRobot]

Thanks. My experience is with different kinds of optical systems so I'm trying to understand what I'm seeing in the context of what I know. And it seems often it's not enough. Even if my general intuition for optics is good, I'm unfamiliar with some of the specifics for any given application that differs from those of my experience.