140 Megapixel Picture of the Sun | Hacker News Reader

140 Megapixel Picture of the Sun

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True color images of the Sun are rare, so just for context, the Sun looks roughly like [1] (the original upload of the Wikipedia "Sun"'s current header image, before it was degraded[2] by its author and others).

Does anyone have a favorite true color image of the Sun? Real or synthetic? I wish I knew of even one created with good research-paper-level care. Searching now, I sank in the usual swamp of artistic bogosity. Perhaps one could take a common visible-band image for grayscale detail, and colorize it with computed limb darkening tint? (Computed tinting like this[3], but there are python astro libraries now.)

[1] https://upload.wikimedia.org/wikipedia/commons/archive/8/83/... [2] https://en.wikipedia.org/wiki/File:The_Sun_in_white_light.jp... used on https://en.wikipedia.org/wiki/Sun [3] https://space.stackexchange.com/questions/16622/need-help-si...

“True Colour” does not really mean much here because colour is a characteristic of visual perception, i.e., it a human observer construct. With that in mind, and disregarding the fact that it is impossible to directly observe, the colour of the Sun would be white because it is the dominant irradiance source around us and an observer would be logically be chromatically adapted to it. It is the reason why the standard illuminant in colour science is D65, i.e. a average spectrum of the sun going through our atmosphere.

> does not really mean much here [...] impossible to directly observe

As misconceptions are common around the Sun, sunlight, and colour, it can be helpful to crosscheck concepts by swapping the Sun for a more familiar object: a light bulb, display, wall, shirt, or elephant.

Imagine an article about a newly energy-efficient light bulb, which included only false-color thermal and near IR images - "Look, less waste heat and wasted light!". Would it seem odd to suggest adding a true-color visible-light photo? What if the authors color graded such a photo to hide a less marketable, say greenish cast?

Years ago, NASA did a traveling museum exhibit on the Sun with lots of colorful images, but not a single white Sun. Now imagine a traveling exhibit on elephants. With colorful thermal IR images of ears as radiators, and false-color images of skin parasite distribution (thus mud baths) and so on. But not a single grey elephant. How odd would that be?

Presented with "A 5-year old asks: The Sun is a big hot ball... what color is the ball?", it's not uncommon for first-tier-U physical-sciences graduate students to answer with variations on "it doesn't have a color; it's lots of different colors; it's rainbow color", reflecting misconceptions around color perception. Which then might be probed with "A 5-year old asks: what color is that shirt?".

"Why does the Sun shine? Fusion!" becomes "Why does the LED light bulb shine? Electricity!", highlighting the incompleteness.

Another crosscheck is seeing how the non-uniform appearance of the Sun (limb darkening) is handled. With the edge/limb appearing darker and redder because of longer sight lines through cooler higher layers.

Is this a “raw” photo or has a bunch of computional photography / AI been applied?

Here is what the author said:

> This image is a fusion from the minds of two astrophotographers, Myself and u/thevastreaches . The combined data from over 90,000 individual images captured with a modified telescope last Friday was jointly processed to reveal the layers of intricate details within the solar chromosphere. A geometrically altered image of the 2017 eclipse as an artistic element in this composition to display an otherwise invisible structure. Great care was taken to align the two atmospheric layers in a scientifically plausible way using NASA's SOHO data as a reference.

> If you're curious how I take these sorts of images, I have a write-up on my website. Check it out here: https://cosmicbackground.io/blogs/learn-about-how-these-are-...

There's no such thing as a "raw" photo.

Even your eyes process certain wavelengths and omit a lot of the spectrum that something like the Sun emits.

Photographers think of "RAW" as the unmodified original data from the image sensor. It is raw in the sense that no further processing has been applied yet to make a human viewable image (or whatever you want to do with it). It would need to be demosaic'd, adjusted for lens distortion, have dynamic range and gamma adjustments, and other things to make a nice image for humans to view.

The “raw” data in so-called “raw” image formats in not unprocessed data from the image sensor. The camera will already have done processing on the data, it’s just not fully processed.

If it was indeed raw data off the sensor, you’d see all kinds of “bad” things such as dead pixels. And camera vendors (obviously?) don’t want you to see that.

> The “raw” data in so-called “raw” image formats in not unprocessed data from the image sensor.

RAW images are completely un-demosaiced and otherwise unprocessed sensor data, dead or stuck pixels and all. It's the job of the RAW converter (whether performed in-camera or post-capture) to hide those in the conversion to a standard color space.

Manufacturers are now blurring the meaning of RAW to be closer to what you imagine. For example, Apple's ProRAW images are demosaiced and heavily processed.

> Photographers think of "RAW" as the unmodified original data from the image sensor. It is raw in the sense that no further processing has been applied yet to make a human viewable image (or whatever you want to do with it). It would need to be demosaic'd, adjusted for lens distortion, have dynamic range and gamma adjustments, and other things to make a nice image for humans to view.

Yes, but even besides that, image sensors only capture a part of the spectrum.

Is a combination image from 3 different spectrums (let's say UV/X-Ray/Visible) raw or no? Is it less or more raw than individual images?

That's what my comment was about.

It’s pretty clear what is meant by “raw photo” here. This is not a raw photo, and probably not really what we’d call a “photo” at all, more like a visualization.

Captured radiant energy was involved in the process, so I think it can be considered a photo. But it’s not raw data straight out of the camera. That being said, a composite timelapse of the night sky isn’t a raw photograph either. I don’t think you find a lot of “raw photos“ in Astro photography

Computational:

> This image is a fusion from the minds of two astrophotographers, Myself and u/thevastreaches. The combined data from over 90,000 individual images captured with a modified telescope last Friday was jointly processed to reveal the layers of intricate details within the solar chromosphere. A geometrically altered image of the 2017 eclipse as an artistic element in this composition to display an otherwise invisible structure. Great care was taken to align the two atmospheric layers in a scientifically plausible way using NASA's SOHO data as a reference. The final image is the most detailed and dynamic full image of our star either of us have ever created. A blend of science and art, this image is a one-of-a kind astrophoto, as the ever-changing sun will never quite look like this again.

The photographer here is one of the biggest users of topaz denoise/sharpening. It's an ai model that is really great at cleaning up back yard astrophotography.

It's considered cheating.

Or the guy is just having fun enjoying his hobby.

The photographer is very upfront about the process, too.

At some point the photo cameras or mobile phones are going to automatically include such denoising features (since it's an artefact of the photo capture, not a visible element) and then people would still call it "#nofilter"

Erm, that point has come since quite a while.

Recent controversy over fake sony moonshots:

https://news.ycombinator.com/item?id=35107601

True, this was a fascinating one :)

*Samsung, though. Not Sony.

Why is it considered cheating? What is it cheating against?

The models are trained on Hubble data. It's cheating against the rest of the astrophotography community if you're just replacing your pixels with NASA's pixels. Mcarthy takes a lot of flack for this and has said he'll back off use of the AI models.

Who are they cheating? If they are upfront about the process, hardly the observer, or..?

I'll answer this here.

He is not upfront about it. Most lay people think that these amazing shots he gets are what is attainable with a backyard telescope. It's not.

It's bad for the same reason influencers using body filters is bad.

140 megapixel computer interpretation of the sun. Much lamer.

Wait so did he make the full-resolution, uncropped image available?

I'm not sure if this is full-resolution, but the uncropped image was posted on his Twitter account:

https://twitter.com/AJamesMcCarthy/status/163864845900280627...

Uncropped: https://nitter.net/AJamesMcCarthy/status/1638648459002806272

The full resolution image is being sold on author's website here: https://cosmicbackground.io/products/fusion-of-helios

The print ready 139 megapixel version costs 50$

I don't quite understand why it is apparently so hard to make a decent photo of the sun. Obviously you would need quite a strong filter to get it dark enough (otherwise the photo will be overexposed), and you need to zoom in since the sun appears not very large from Earth. But other than that?

“A geometrically altered image of the 2017 eclipse as an artistic element in this composition to display an otherwise invisible structure. Great care was taken to align the two atmospheric layers in a scientifically plausible way using NASA's SOHO data as a reference.

The final image is the most detailed and dynamic full image of our star either of us have ever created. A blend of science and art, this image is a one-of-a kind astrophoto, as the ever-changing sun will never quite look like this again.”

Would it be fair to say this is an impressive computer rendering of the sun?

Are there any real, untouched, photos of the sun available? Is it true the sun is actually white?

Great image. and, SpaceX should totally offer cremations where you can get shot into the sun.

Food your repeat that please?!

Make sure you view it with appropriate shielding for your eyes!

The bright streak above and to the left of the center of the image looks like a phoenix or maybe a dragon!

You can almost see, were the center of gravity of the solar system steers the pot..

I wonder why we can't model the sun. It would seem to be simpler than say modeling the weather on Earth.

Why would it be simple?

No butterflies.

https://en.wikipedia.org/wiki/Magnetohydrodynamics

Sure we do. It is different and no simpler than modeling weather. Weather at least has the advantage of a 3D system decomposing into a 2D sphere X 1D height dimension via a thin shell approximation, but also has the complexity of humidity. The Sun is intrinsically a 3D system, but has electromagnetic complications.

> the complexity of humidity

Without the nonlinearity of water vapor<=>liquid<=>ice, Earth weather predictions would be pretty darn easy.

IANA astrophysicist, but I'm guessing the same would be true about the Sun without magnetic fields.

What does “model” even mean here?

make the sun into a set of mathematical equations, like the way gargantuan was modeled in interstellar https://github.com/sirxemic/Interstellar or the way schrodinger wave equations model an atom. [libretexts schrodinger equation] https://chem.libretexts.org/Courses/University_of_California...

My question still stands? _What_ aspect are you modeling exactly? The Sun as a celestial body? The fluid dynamics of the surface? The nuclear process going on in the core?

You can’t just entirely “model” something as complex as a star anymore than you can do large scale simulations of the universe at the atomic level. If we could we would be much more ahead as a civilization.

1. The sun has a (weak) magnetic field that affects how its gas moves, which we don't fully understand. 2. There is a Coriolis force all the way down to the center of the sun, which makes the gas move in weird ways. 3. As a sphere of fluid, the sun supports vibrational modes that we are only just beginning to understand. (See work by e.g., Conny Aerts) 4. We can't really see into the sun’s interior, although understanding the vibrational modes will help.

Anecdotally, Argentina tried it[0]. The project was sold to Peron as way to create artificial suns.

0:https://en.wikipedia.org/wiki/Huemul_Project

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