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Comment by sbierwagen | Hacker News Reader

Alpha Centauri is 4.344 light years away and about 0.00930093 AU in diameter, and if my math is right should subtend 3.12x10^-25 arc seconds.

The Oculus Quest 2 has a horizontal FOV of 97 degrees. In order for α Centauri to cover two pixels, you would need a display with 6.2179487x10^26 horizontal pixels. 621 yottapixels. Something like a hundred sextillion times "4K" resolution. And that's linear resolution, tag on some more orders of magnitude for display area.

There is a reason parallax is used to measure distance to stars, rather than directly measuring their visual diameter.

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The atmosphere blurs the starlight in the last miles of its journey. We’ll need a astrophotographer here, but I’m pretty sure Capella, in October, in the norther latitudes is larger than a human eye pixel equivalent. The atmosphere really messes with it at that time. I’ve watched it across a cool,lake with warm surface air through binoculars and it was flashing red to blue at about 8 times a second and seemed large. It’s a bright star so remains visible after being spread.

Furthermore they are presuming that the eye’s optics and “pixels” are idealised: they have rather a myopic point-of-view.

Even in outer space, with no atmospheric aberration, there will be some blur for anyone with less than absolutely perfect eyesight.

There will be a point-spread-function because our optics are not ideal (especially with bright point sources), and blur will result from a variety of causes.

> there will be some blur for anyone with less than absolutely perfect eyesight.

Computer graphics are meant to be perceived through human eyeballs. So we can count on the eyes continuing to blur point lights whether you're looking at a screen or at outer space.

It's not that simple. Computer graphics are (currently) displayed on a flat 2D plane at some single distance from the eyeball. Typical vision defects affect different distances differently. Think "reading glasses" vs "driving glasses".

Also, the game might be simulating an experience from a character's point of view, and expect the player to be wearing glasses to correct their personal vision defects (to the extent possible).

I poked the numbers above into a Rayleigh criterion calculator and got a number measured in thousands of light years? My comment on if my math was correct was prescient. 10^-25 showing up should have been a hint to myself, whoops.

(The calculated horizontal resolution required for a 2 pixel wide star from the original post should instead be 100,009,624)

The corrected number for star apparent diameter should be 0.006983 arcsec. Depending on how finely you want to resolve the disk, that would take somewhere between a 70 to 140m wide telescope. (With 400nm light)

The largest optical telescope currently under construction is 39.3m wide: https://en.wikipedia.org/wiki/Extremely_Large_Telescope

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