14 replies to this topic

[COMET5]

Hello, I am very interested in images or photographs of celestial objects (stars, clusters, nebulae, etc.) that are as faithful as possible to their real color. I would prefer to find them in books rather than on the Internet. Do you know of any books of this type?

 

Let me explain, I recently read that the Hubble website had a section in its photo archive (by the way, I have not found that section on its website) where it exhibited photos made with techniques so that the color of those photos was the same. closest possible to its real color, how a person would see it if they traveled near that celestial object. Textually it said:

 

"The types of spatial photography:

 

On the Hubble website there is a section dedicated to the processing of the images captured by the famous observatory. They classify them into three types depending on how they are edited and what they are trying to achieve:

 

Natural color: these are those that remain after processing three images obtained from filters close to the colors green, red and blue. What we would see if we were able to travel to the event that appears in the photo. To achieve this type of images, it is essential to assign the colors to the exposures in chromatic order, that is, the shortest wavelength must correspond to blue, the medium to green and the widest to red."

 

I would love to get a book with images that are as similar as possible to the real image that we would see if we traveled to that object.

 

I recently bought the book "Photographic Atlas of the Constellations" by Slawik and Reichert. The book is a true gem, I highly recommend it to everyone, the quality of the photos, the binding, the book itself, the large size it has... I repeat, a truly marvelous book, don't think twice and buy it (I have no relationship with the authors, ha ha, but I liked it so much that I would like other astronomy fans to enjoy it too).

 

Well, one of the cool things about this book is that about the magnificent photos of the sky it has, they say that they are made with special techniques, which means that the different brightnesses of the stars are captured as they are perceived by the human eye, thus like the intrinsic colors of the brightest stars. But it contains many photos with spectacular colors of nebulae, and I don't know if they are "real" colors or not. If someone has this book and knows exactly what these photographic techniques mean, please explain it, I would be delighted.

 

All the best.

[havasman]

Which "real" color? Visually perceptible colors are limited by our perception's bandwidth. Image processors assign values from selected capture bandwidths. Extended energy bandwidths exist outside either our visually perceptible bandwidths or those selected from the capture/process options.

 

That's why radio or infrared astronomy can "show" objects very differently from what we see visually or capture via normal astrophotography. If we could see the entire energy spectrum then maybe we could speak of real colors.

Edited by havasman, 07 March 2024 - 06:13 PM.

[Astrojensen]

 

I would love to get a book with images that are as similar as possible to the real image that we would see if we traveled to that object.

Extremely few objects would show color, even if we were much nearer to them. Think of the Milky Way. We are inside it, yet it's dim and show no color. All other galaxies would be the same. 

 

I've seen color visually in a few planetary nebulae and the Orion Nebula with a large telescope, but they were not anywhere near as strong as in photos. 

 

That doesn't mean we can't try making photos that show the colors we would see, if our eyes suddenly became much, much more sensitive. Whether there are any such books, others will have to tell. I'm not aware of any book that specifically address this particular topic. All newer astronomy books I can think of have many images in false or enhanced colors.

 

 

Clear skies!

Thomas, Denmark

[bobzeq25]

There is a book that explains this AND has some fabulous images.

 

If you want to understand color in astrophotography, it's an ESSENTIAL reference.  Written by professional astronomers.

 

https://www.amazon.c...g=UTF8&qid=&sr=

 

Bottom line (but DON'T let it stop you from buying the book).  There is no such thing as real color in the images you see.  Professional astronomers use images mostly for public outreach.  For serious work they use very narrow filters or spectroscopes, and process the numeric data.

 

Don't get the Kindle, the hardcover has amazing "pretty pictures".

 

One underlying reason.  These objects are so dim, they'd look mostly gray to your eyes.  In order for your eyes to see color in a DSO, you amplify color by stretching the data, and dialing up the saturation (sometimes this occurs in the stretching tool, arcsinhstretch is an example).  Whereupon, you can no longer call the color "real".

 

Want to understand this?  Get the book or look at a lot of amateur opinions.  Your choice.  <smile>

 

The authors are NOT amateurs.

 

https://www.kimarcand.com/about

 

https://www.uaa.alas...y/rector.cshtml

Edited by bobzeq25, 07 March 2024 - 04:26 PM.

[COMET5]

OK I understand. But a question:

 

If I were to travel in a spacecraft near the Orion Nebula,

 

Would I see with my eyes those red, blue, violet, etc. colors that we see in the classic photos of books?

 

Would I see with those colors, but more subdued?

 

Would I see in gray and white tones?

 

Photo link:

 

 

https://www.elmundo....1365501157.html

 

  By the way, the book looks very cool, I will buy it, thank you.

 

 

[Sketcher]

Colors are not real.  Seriously.  I've explained this in past postings.  So, here I'll just suggest googling: "Are colors real?"

 

Really, it doesn't matter which book of photographs you choose.  Regardless of the book chosen, the colors in the photos will not be real.

[COMET5]

I understand now.

 

In this video he explains my question perfectly. I was very surprised that, if you traveled to a nebula, you would hardly see colors (because ours are imperfect and only capture a small piece of the spectrum)

 

This is the link to the video:

 

 

 

 

 

https://www.youtube....h?v=OnN7sR3p6vk

[Todd N]

Colours of the Stars by David Malin and Paul Murdin

 

A book from the old photographic plate days. A presentation on the color of astronomical objects and accurately representing them with the photographic materials of that time. Again, not that the human eye would see most of this which it won't. Visual and astrophotography are two different worlds.

[mikemarotta]

https://www.amazon.c...g=UTF8&qid=&sr=

 

 

Thanks for the recommendation.

 

I am going to pick it up at my local library today. (I work on the University of Texas campus and this book is in the Math-Physics-Astronomy library.) I am really not a fan of the ever-rosier Rosettes that we see here. Astrophotography is art, not science. That said, though, epistemology tells us that every sensation is a transduction. That was Immanuel Kant's problem - and Plato before and everyone after. A bee does indeed see the same flower you do, but she sees it differently. It is still real for both of you. 

 

Thanks,

Mike M.

[dawnpatrol]

Colours of the Stars by David Malin is an interesting and beautiful book that wades into the art and science of stellar photography. Highly recommended.
 

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[Tony Flanders]

OK I understand. But a question:
 
If I were to travel in a spacecraft near the Orion Nebula,
 
Would I see with my eyes those red, blue, violet, etc. colors that we see in the classic photos of books?
 
Would I see with those colors, but more subdued?
 
Would I see in gray and white tones?

You can answer that question for yourself by viewing the Orion Nebula through a big telescope. Color vision varies wildly between individuals, so I cannot possibly guess what you would see.
 
Regardless, the colors certainly wouldn't appear nearly as saturated as they do in typical photos. I definitely see a greenish tint in the brighter parts of the Orion Nebula, together with some reddish streaks. But I would describe them as very subtle pastels.

[mikemarotta]

There is a book that explains this AND has some fabulous images.

If you want to understand color in astrophotography, it's an ESSENTIAL reference.  Written by professional astronomers.

The authors are NOT amateurs.

 

 

Thanks for the recommendation.

I am going to pick it up at my local library today. 

It has a lot of pretty pictures and the cutlines ("captions") explain how they were processed and post-processed from data collected from different telescopes with different filters and at different wavelengths and then merged into these presentations. The narrative is directed at a very general audience and I imagined myself reading it as a 10-year old. 

 

These telescopes aren't like the one sitting in the corner of your aunt and uncle's living room. They are big. And by big, we mean as big as a building. Telescopes, especially visible-light ones, are often measured by the diameter of their primary mirror. This is the main mirror that gathers and focuses the incoming light. The larger the mirror, the more light the telescope can collect and the fainter the objects you can see. A top-of-the line amateur telescope may have a mirror that is 24 inches (0.6 meters). That's two feet across. To compare, the primary mirror of the Gemini North telescope is 27 feet (8.2 meters) across. 

 

In addition to their size, these telescopes are also expensive. You can get a low-end amateur telescope for only a few hundred dollars. A top-end amateur telescope  can cost hundreds of thousands of dollars. Professional observatories cost in the hundreds of millions, not to mention the cost of operating them. (Page 136)

 

I found it easy to agree with the statement in Chapter 11: "Photoshopping the Universe: What Do Astronomers Do? What Do Astronomers Not Do?" that you should not add or subtract stars from an image. More instruction is provided in Chapter 12: "The Aesthetics of Astrophysics: Principles of Composition Applied to the Universe." The narrative and illustrations explain well-known optical illusions. I recommend the lessons to anyone who enjoys the colors in the Orion Nebula.

 

Note that the Preface was written by David Malin (Colours of the Stars / by David Malin and Paul Murdin; Cambridge, 1984).

 

Thanks,

Mike M.

Edited by mikemarotta, 16 March 2024 - 01:12 PM.

[SteveCollyer]

You can answer that question for yourself by viewing the Orion Nebula through a big telescope. Color vision varies wildly between individuals, so I cannot possibly guess what you would see.
 
Regardless, the colors certainly wouldn't appear nearly as saturated as they do in typical photos. I definitely see a greenish tint in the brighter parts of the Orion Nebula, together with some reddish streaks. But I would describe them as very subtle pastels.

I also see a lot of green in M42

[Nightfly]

Photography of all kinds are representative of color, as it is an artifice of reality. So is the human eye, which evolved to be useful for survival.  The eye has a small window to the available spectrum of light, known as visible light. 

 

Much is relative to human vision and in the case of photography, photographic materials - to include emulsions and sensors.  Modern sensors may be more linear than film, however human vision is especially nonlinear.  

 

David Malin used the tri-color methods, which included three seperate exposures on B&W film through RGB filters to deliver as "true" a color as possible.  This is similar to Kodachrome,  which was a three layer b&w film.  The colors were "injected" by Kodak in the development process.  

 

All methods are tainted by the limits of technologies, and our experience of colors are subjected to the limits of human vision.

 

Perhaps a better way to put it is, what is true to human vision?  I cannot say.  We all have preferences in photography.   I prefer the simplicity of the B&W image.  I like the work of E.E.Barnard, and those that followed.  All photos are an artifice.

 

 

 

[bobzeq25]

 

I found it easy to agree with the statement in Chapter 11: "Photoshopping the Universe: What Do Astronomers Do? What Do Astronomers Not Do?" that you should not add or subtract stars from an image.

I totally disagree with that.  If you're trying to image a galaxy, and the image contains a lot of stars that distract from that, I see nothing wrong with judicious star reduction.  PixInsight (the developers are not exactly fans of a heavily artistic approach) has an excellent MorphologicalTransformation tool for doing just that.

 

And here's the "this is big trouble" question.  If a bright star (or bright stars) in an image are bloated, isn't that really an artifact of the camera?  Isn't it more objectively realistic to do something about the bloated star or stars?  After all, they're not really 5X as large as dimmer stars, and don't appear to the eye to be so.
 

Edited by bobzeq25, 26 March 2024 - 01:16 AM.