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Comment by Jaruzel | Hacker News Reader

Are the images natural colour, or have they been 'enhanced' in any way? i.e. is Neptune really that blue?

I see this question a lot. I used to have an obsession with 'true color'; images felt fake otherwise. Artificial.

I'm a working scientist now, and my view has changed. I realize how limited our senses are. How much of the world--of the universe--I'd miss by restricting it to just what my eyes can see natively. Even among colors that I can see, but perhaps the signal is too faint ... I'm a lot more tolerant of color-mapped images now. I don't see them as artificial anymore, but as beautiful and transcendental. A window into a hyper-spectral world normally invisible to me. It's really something special. I wish I could share this perspective with more people.

I think the beauty is lost on me when I don't know what the color means. I either want the real deal or to know what the mapping is so I can appreciate that. Otherwise it's just a pretty picture.

> or to know what the mapping is

Agreed! This is important. Scale bars would be nice too, as well as info on other pre-/post-processing. Usually all this is in an associated publication (which is hopefully freely available), since it usually takes a surprising amount of information to fully understand an image like this.

> beauty is lost on me > pretty picture

Pick one ;) Sometimes we can find things beautiful without fully understanding them (arguably this is always the case). For me, knowing whether it’s derived from real measurements is what matters. But everyone’s threshold is different. I’ve seen beautiful simulated data too, but that’s something different again — more like the beauty of an equation to me.

I think it boils down to two things (at least it does for me):

- If the picture is shown as if it was a photo, how similar is it to what I'd see if I were magically transported in a spacesuit into object's vicinity?

- If the picture is an obvious false-color render, does it have a reasonable color map, or some "artist's impression"?

It's a real eye-opener when you realize that our eyes are no more "true color" than a CCD... I didn't really get that until I took a graduate optical observing class.

Alex Grey studied cadavers at Harvard for years. His art tries to show the true medium, not one limited by visible light. Sort of like what Superman might see. Our bodies are emanating light in a spectrum of frequencies (Planks law.) All this light is leaving our bodies at C, whiles all the light from the universe is coming at us, our "light cone." We see the surface of bodies..but the actual substance of reality has interfering rippling waves emanating and being absorbed..not unlike a pool. So the next time someone tells you someone is ugly, remember that the visible light surface is just the beginning..

https://m.alexgrey.com/art/paintings/soul/alex_grey_humming_...

The artist of drawings for Scientific American for many years made his drawings super-real by emphasizing components of interest. And these were black-and-white.

The advantage of MUSE is that you get all color information, i. e. the flux at any wavelength from blue to red. In principle, one can use this together with the sensitivity curve for our eyes to construct a natural image. In this case, I think, they tried to imitate the color scheme from the Hubble image which is more limited.

In short: Not sure how realistic this is, but one could make a realistic image from the new data.

So MUSE is hyperspectral? there's a full spectrograph at each pixel?

Exactly! One datacube that comes out from the instrument contains 300 x 300 spectra. This is actually the main capability of the instrument which has 24 individual spectrographs. Here's a nice animation of the path the light takes inside MUSE: https://www.youtube.com/watch?v=-fh2Y6Zyhwc&feature=youtu.be...

Awe-inspiring. You can see the individual spectrographs at https://youtu.be/-fh2Y6Zyhwc?t=1089

Could one use that information the other way around to make estimates for expected "missing data" in Hubble images taken in areas where VLT has not looked yet, for example to decide where to look next?

<something something throw machine learning at it cliché>

Not sure if you meant it like this but redshift estimation comes to my mind. The farther away a galaxy is, the redder it becomes. You can measure the distance (redshift) from galaxy spectra (with MUSE for example) but not from directly HST images. This mapping color -> redshift is called photo-z and was tested with MUSE data in an very famous area observed with HST, the Hubble Ultra Deep field. https://arxiv.org/abs/1710.05062

here's a natural color image of neptune:

https://upload.wikimedia.org/wikipedia/commons/6/63/Neptune-...

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