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Originally Posted by Merlin66
Hmmm
reading up to understand this "ever expanding star"....
I think the issue is that I'm hung up on the Airy Disk as being the manifestation of the size of the star image....
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It appears so. I don't know what else to say to persuade you otherwise. How exactly do you come to that conclusion in the face of what is on Wikipedia and what I explained and demonstrated?
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and the Airy pattern of ever decreasing rings as being so low in relative intensity relative to the "core" that even if they were over-over exposed they would never reach the intensity values of the Airy disk, and would, therefore, only contribute the the "wings" of the image and not the "flat topped" over exposed, saturated area seen in and around the Airy disk..
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The latter is just not true.
If George Bidell Airy was able to distinguish the second ring with his puny human eyes, what do you think a long exposure would show?
One last example of where you're going wrong;
Let's say my annual income is $100.000 (my CCD well depth) and I'd like to get a loan of $1000 (photons to disperse, aka star brightness). My bank offers a rate of 17% (percentage of photons dispersed outside the central fuzzy blob, or the PSF for the non-central fuzzy blob).
I'd be paying $170 per year - peanuts! It is easily serviceable with a $100.000 income and hardly noticeable when compared to my income (it's just 0.17% of my income).
By your logic I could just as easy take out a loan of $100.000.000. You seem to think the 'interest rate' (PSF) somehow is an absolute value, whereas it is a multiplication factor. Pick a high enough loan (star brightness) and it *will* start to matter. In the example of a $100.000.000 loan, I'd be paying $17.000.000 interest. I would need 170.000% my annual income (170 CCD wells) just to service the interest!
You're arguing the bump from 0.17% to 170,000% of my income isn't noticeable.
I really don't know what else to say or do. I've attached results of the TIFF multiplied by 800%, 3200%, 32000% and 320000%, just to show you it *does* grow, even though you can't see the light being spread at low energy levels.
FYI, the the initial PSF (i.e. the star in the TIFF) was obtained by creating a circular aperture (e.g. a white circle with a diameter of the 256 pixels) and then performing a forward Fourier transform and taking the magnitudes of the resulting complex numbers. Just like the math in the Wikipedia article.