Nova photos are star-field photos. Add an extra dot.

Very nice. I'm going to try tonight. Thanks, Joe --- On Mon, 11/30/09, Patrick Wiggins <paw@wirelessbeehive.com> wrote: From: Patrick Wiggins <paw@wirelessbeehive.com> Subject: Re: [Utah-astronomy] Nova in this evening's sky (Pictures) To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Monday, November 30, 2009, 1:14 AM I got a few pictures of the nova as it was about to transit. Admittedly it's not much to look at.  It measured about magnitude 9.05. But that makes it all the more astounding to me that the guy was able to find it with small binoculars and no computer.  Apparently he has the sky memorized down to who knows what magnitude.  Impressive. Unfortunately 9th magnitude is pretty bright for my setup so even with a red filter I was only able to go 2" (3" saturated the chip).  But it's there. I could have gone longer to bring out the background but that would have had the nova saturating the chip and made accurate magnitude determination impossible. I could not find any amateur pre-discovery shots so I used the POSS.  Here's the POSS image with one of mine next to it.  Arrows indicate the nova before and after. If the weather holds I'm going to see about getting pictures every clear night for a while so I can see how it fades. http://users.wirelessbeehive.com/~paw/temp/nova01.jpg Looks like the progenitor star is listed in the Hubble Guide Star catalog as 5325:1837.  Position (2000): RA 04 47 54 Dec -10 10 43 patrick On 29 Nov 2009, at 12:22, Patrick Wiggins wrote:

+++++ Nova in Eridanus This is an AstroAlert from Sky & Telescope. NOVEMBER 29, 2009 by Roger W. Sinnott An 8th-magnitude nova was discovered on November 25, 2009, by Koichi Itagaki of Yamagata, Japan. The new star lies in northeastern Eridanus, 6.9° west-southwest of Rigel. In an e-mail sent late on the evening of November 28th, Sky & Telescope Senior Editor Alan MacRobert writes, "Just spotted the nova in my 10x50 binocs on their wooden shoulder frame. Barely visible through the bright moonlight at about mag 8.4." The find was announced on CBET 2050, issued November 25th by the Central Bureau for Astronomical Telegrams at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts. Itagaki was using an 0.21-meter (8.3-inch) patrol camera, but within 15 minutes he secured a confirming image with an 0.60-meter reflector. The nova lies at right ascension 4h 47.9m, declination –10° 11' (equinox 2000.0). +++++

It'll be about 7 degrees to the upper right of Rigel as Rigel is rising this evening about 8.  Well placed for viewing as it transits about 1 tomorrow morning, about 40 degrees above the horizon as seen from SLC.

patrick

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Hi Patrick, I had the same awful problem last night -- frost! Today I'm buying a little hair dryer. Also, anyone have any suggestions about what to use for a dew shield? I bought something earlier but it's too rubbery to maintain a shape. Thanks, Joe --- On Tue, 12/1/09, Patrick Wiggins <paw@wirelessbeehive.com> wrote: From: Patrick Wiggins <paw@wirelessbeehive.com> Subject: Re: [Utah-astronomy] Nova in this evening's sky (Pictures) To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Tuesday, December 1, 2009, 1:34 AM Hi Joe (and anyone else interested), I got 50 shots tonight and their average is about .15 magnitude fainter than the same time last night. patrick On 30 Nov 2009, at 10:55, Joe Bauman wrote:

Very nice. I'm going to try tonight. Thanks, Joe

--- On Mon, 11/30/09, Patrick Wiggins <paw@wirelessbeehive.com> wrote:

From: Patrick Wiggins <paw@wirelessbeehive.com> Subject: Re: [Utah-astronomy] Nova in this evening's sky (Pictures) To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Monday, November 30, 2009, 1:14 AM

I got a few pictures of the nova as it was about to transit.

Admittedly it's not much to look at.  It measured about magnitude 9.05.

But that makes it all the more astounding to me that the guy was able to find it with small binoculars and no computer.  Apparently he has the sky memorized down to who knows what magnitude.  Impressive.

Unfortunately 9th magnitude is pretty bright for my setup so even with a red filter I was only able to go 2" (3" saturated the chip).  But it's there.

I could have gone longer to bring out the background but that would have had the nova saturating the chip and made accurate magnitude determination impossible.

I could not find any amateur pre-discovery shots so I used the POSS.  Here's the POSS image with one of mine next to it.  Arrows indicate the nova before and after.

If the weather holds I'm going to see about getting pictures every clear night for a while so I can see how it fades.

http://users.wirelessbeehive.com/~paw/temp/nova01.jpg

Looks like the progenitor star is listed in the Hubble Guide Star catalog as 5325:1837.  Position (2000): RA 04 47 54 Dec -10 10 43

patrick

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Thanks Patrick, I'm so discouraged I've packed it in until Spring. Hey, can you let us see 'em when you've accumulated a week or so worth of nova photos? Sounds like blog fodder! Thanks, Joe --- On Tue, 12/1/09, Patrick Wiggins <paw@wirelessbeehive.com> wrote: From: Patrick Wiggins <paw@wirelessbeehive.com> Subject: Re: [Utah-astronomy] Nova in this evening's sky (Pictures) To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Tuesday, December 1, 2009, 2:17 PM On 01 Dec 2009, at 10:23, Joe Bauman wrote:

Hi Patrick, I had the same awful problem last night -- frost! Today I'm buying a little hair dryer. Also, anyone have any suggestions about what to use for a dew shield? I bought something earlier but it's too rubbery to maintain a shape. Thanks, Joe

There's always the store-bought plastic, electrically heated dew caps. But being the cheap skate I am I made my own out of the dark colored foam material mechanics use to line the bottoms of tool box shelves.  It comes in rolls.  Cut to the appropriate length and sew the ends together to form a tube.  The fact it's foam keeps the weight down and also seems to help with insulation. I think I got mine at the downtown Sears (memory's fuzzy after all these years). Good luck, patrick _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com

Many thanks, Jo. I will have to try that. I grew so discouraged that I hauled my scope upstairs for the winter, determined not to take it outside until Spring. It was about a 14' lift of something that weighs more than 100 pounds counting the hand truck I put it on. But I'll probably try again next new moon. Best wishes, Joe --- On Wed, 12/2/09, Josephine Grahn <bsi@xmission.com> wrote: From: Josephine Grahn <bsi@xmission.com> Subject: Re: [Utah-astronomy] Nova in this evening's sky (Pictures) To: utah-astronomy@mailman.xmission.com Date: Wednesday, December 2, 2009, 12:03 AM Hi Joe, You can also go to Regional Supply Co (http://www.regionalsupply.com/) and take a look at some of the thin black acrylic sheets that they have. We bought some, cut it to shape, and used velcro to hold it in place.  One piece of velcro to hold the two overlapped edges together, and more to hold it to the tube. If you make it nice and long, the frost will not bother your scope at all, and it has an added advantage of screening your mirrors from low light sources. For storage, you can usually wrap it around the tube, if you cut it wide enough. If you are worried about light bouncing on the shiny plastic interior, you can "matte" it with a quick scrubbing of steel wool. Jo Quoting Joe Bauman <josephmbauman@yahoo.com>:

Thanks Patrick, I'm so discouraged I've packed it in until Spring.  Hey, can you let us see 'em when you've accumulated a week or so  worth of nova photos? Sounds like blog fodder! Thanks, Joe

--- On Tue, 12/1/09, Patrick Wiggins <paw@wirelessbeehive.com> wrote:

From: Patrick Wiggins <paw@wirelessbeehive.com> Subject: Re: [Utah-astronomy] Nova in this evening's sky (Pictures) To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Tuesday, December 1, 2009, 2:17 PM

On 01 Dec 2009, at 10:23, Joe Bauman wrote:

...

Hi Patrick, I had the same awful problem last night -- frost! Today  I'm buying a little hair dryer. Also, anyone have any suggestions  about what to use for a dew shield? I bought something earlier but  it's too rubbery to maintain a shape. Thanks, Joe

There's always the store-bought plastic, electrically heated dew caps.

But being the cheap skate I am I made my own out of the dark colored  foam material mechanics use to line the bottoms of tool box  shelves.  It comes in rolls.  Cut to the appropriate length and sew  the ends together to form a tube.  The fact it's foam keeps the  weight down and also seems to help with insulation.

I think I got mine at the downtown Sears (memory's fuzzy after all  these years).

Good luck,

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Looks great! -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of David Rankin Sent: Tuesday, December 01, 2009 6:52 PM To: Utah Astronomy Subject: [Utah-astronomy] M51 reprocessed I didn't realize how bad the processing on my M51 shot was until I got home. I started over on a real monitor, and here is the new result. I had way over saturated the reds before. http://www.slas.us/gallery2/main.php?g2_itemId=2718&g2_imageViewsIndex=1 Cheers, David Rankin _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com

Don't beat yourself up, David. Saturated colors in astronomical images are all fake. We try to approach what the various objects might look like if they were actually bright enough to trigger the color receptors in our eyes, but all deep-sky astronomical images are really just art, when it comes right down to it. An article in S&T some years ago (and even a "Sky-Wise" cartoon by Jay Ryan) demonstrated that even if we were much closer to these galaxies than we are, they would look about like the Milky Way looks to the naked eye from a dark site. Impressive, yes, but not tinted blue and red. Even if we were immersed in the Orion Nebula, the brightest parts would appear as a colorless, grey vapor instead of the red we are used to in photographs, or are on the verge of detecting visually in large aperture scopes. The colors are thanks to our insturmentation. The challenge in astro-imaging is to pursue ever smaller star images- crisp, tight focus. Diffraction-limited imagery. The colors are just what pleases the eye. This one does match what we are used to seeing much more closely. Keep up the good work! On Tue, Dec 1, 2009 at 6:52 PM, David Rankin <David@rankinstudio.com> wrote:

I didn't realize how bad the processing on my M51 shot was until I got home. I started over on a real monitor, and here is the new result. I had way over saturated the reds before.

http://www.slas.us/gallery2/main.php?g2_itemId=2718&g2_imageViewsIndex=1

Thanks Guys, The way I think about it is this. As Joe stated, our eyes are not so great at picking up deep space objects because of the way they are designed. The colors coming off of these objects are fairly consistent. As we all know when night falls, our cones turn off and rods turn on...rods are good with black and white, and movement, but not color. When I stare at M42 for a minute or two, I can make out some reds and blues as my cones start to turn back on because the object is so bright, even with my 10" OTA. The CMOS sensor is not inventing any new colors for these objects, it is simply designed to pick up wavelengths of the electromagnetic spectrum from around the start of UV light, into Infrared light. The CMOS is naturally good at detecting IR light, and has to have a filter put in front of it to block that light for your average end user photographer (I removed this filter to make the camera shoot IR again). You can tweak them a lot, but for the most part, each gas is going to give off its signature light wavelength in the electromagnetic spectrum. Just because we cant see it with our eyes doesn't mean that is not the real color. I think the camera is doing a much better job than our eyes of seeing and capturing the color. Another big problem with our eyes is how small they are. The average pupil can open to about 7mm, this is not a lot of light capture to start with. A 9.25 inch mirror equates to about 1126 eyeballs worth of light gathering power. On top of that, our brain is refreshing our vision at around 30Hz, so our photon capture is being refreshed/drained very fast. A camera does not have this problem, it can just keep collecting photons as long as you leave it open. When you shoot an primarily Ha Nebula, it is always red, that is because the excited hydrogen is giving off light just off the red side of visible light in the infrared range, when you shoot a reflection nebula, it is blue, that is because light tends to scatter in the blue wavelength, and not in the red. Our sky is blue for the same reason that reflection nebulae come out blue. I guess my main point is this, the colors are accurate, the instruments are just better at capturing them than our puny little eyeballs. Even when you get a "false color" image, it is usually just a compilation of the selective shooting of each gas, as each gas will give off light in a different wavelength, so in reality, its not really false color, its selective color. I've heard that if you represented the electromagnetic spectrum as a film strip that went up the west coast of the USA, what we see with our eyes, visible light, would take up just one frame out of that film. O.o Anyway, I thought I would share some thoughts on this. If I made any mistakes, please point them out. Always like to learn more about this stuff. David Rankin Joe Bauman wrote:

Color in space is a topic that has puzzled me too. (We can get philosophical and wonder if one person perceives vision itself the same as another, which is challenging to think about.) Concerning color photos of deep-space objects, I think the reproductions do have some validity. That is, if five astrophotographers using the same filters and exposures compare their work, they would be similar. There is a basis for the color, some objective reality in space. The tints are not the same as we can see with our eyes because our eyes are highly limited instruments, needing a certain intensity of light to see color at all. And there are plenty of electromagnetic wavelengths out eyes can't perceive at all. When CCD cameras gather light over long periods, they are improved versions of our eyes, accumulating and multiplying the photons, so they recognize color in dim objects we could never detect without such help. But the colors really are there in the sense that we can record them. Probably actual wavelengths of colored objects in space could be measured to give particular tints and shades.

But I'm also sure there is a big component of art involved in making astrophotos. We need to take into account such things as how much the atmosphere distorts the colors, making the problem awfully complicated.

That's just my opinion and maybe others in the group could improve my understanding.

-- Thanks, Joe

--- On Tue, 12/1/09, Chuck Hards <chuck.hards@gmail.com> wrote:

From: Chuck Hards <chuck.hards@gmail.com> Subject: Re: [Utah-astronomy] M51 reprocessed To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Tuesday, December 1, 2009, 11:23 PM

Don't beat yourself up, David. Saturated colors in astronomical images are all fake. We try to approach what the various objects might look like if they were actually bright enough to trigger the color receptors in our eyes, but all deep-sky astronomical images are really just art, when it comes right down to it. An article in S&T some years ago (and even a "Sky-Wise" cartoon by Jay Ryan) demonstrated that even if we were much closer to these galaxies than we are, they would look about like the Milky Way looks to the naked eye from a dark site. Impressive, yes, but not tinted blue and red. Even if we were immersed in the Orion Nebula, the brightest parts would appear as a colorless, grey vapor instead of the red we are used to in photographs, or are on the verge of detecting visually in large aperture scopes. The colors are thanks to our insturmentation. The challenge in astro-imaging is to pursue ever smaller star images- crisp, tight focus. Diffraction-limited imagery. The colors are just what pleases the eye.

This one does match what we are used to seeing much more closely. Keep up the good work!

On Tue, Dec 1, 2009 at 6:52 PM, David Rankin <David@rankinstudio.com> wrote:

...

I didn't realize how bad the processing on my M51 shot was until I got home. I started over on a real monitor, and here is the new result. I had way over saturated the reds before.

http://www.slas.us/gallery2/main.php?g2_itemId=2718&g2_imageViewsIndex=1

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I'm still not sure if I understand what your saying right. "It's analogous to looking at an x-ray or image of any other spectral region that is beyond our unassisted vision, either because of wavelength or intensity threshold." Our ability to see an object does not dictate what wavelength of the electromagnetic spectrum it gives off. Regardless of how dim it is to our eye. Just because we are not able to see it that way, doesn't mean it is not that way. Each gas will always absorb and emit a very specific wavelength of the electromagnetic spectrum. I understand that our eyes are very very limited in seeing what is actually there, and that each object would never look like what it does in a photo to the naked eye, but that is just to the naked eye, the elements giving off those wavelengths are still actually there, and actually those wavelengths. Digital cameras are calibrated to reproduce the same section of the electromagnetic spectrum that our eye sees, the same way the eye sees it. They are not picking up other parts of the invisible (to us) spectrum and assigning colors to them. This is how they measure the composition of the universe, galaxies, stars ect. I don't think imaging visible light, and representing the X-ray part of the spectrum are the same thing. Visible light will actually emit the photons that our eyes can see, when you image a galaxy, or nebula, your simply collecting more of the light we *can* see. We have to do a false color map outside of visible light, to represent those other energy levels. If our eyes could collect photons without updating at 30Hz, we would be seeing much like what the photographs are. "Galaxies do not look like their photos, in real-time, naked-eye views, regardless of viewing distance. Ever. The images are always representational and more analagous to art (or even a sort of intensity map of flux levels) than a "xerox copy" or a daylight snapshot of an everyday scene." I think galaxies would look very like their photos if our eyes were more sensitive to them. Again, the photographs are calibrated to pick up the same section of the spectrum that our eyes do. They are not creating any new colors, they are just gathering more photons over a longer period of time. "There is no doubt that she would see galaxies as being tinted differently than we do." I understand that the perception of the electromagnetic spectrum is all about calibration, but the point is this, the average of all deviations of how each eye picks up light will still fall in a mean of visible light, and for the most part humans eyes are calibrated to see the section starting at the end of UV as violet, and and the beginning of IR as Red, based on those wavelengths. This is a direct function of the temperature of our star. If we lived on a planet closer to a cooler star, our eyes would have evolved to see light in the IR section of the electromagnetic spectrum as cooler stars give off much more light in this range. So, what I'm saying is that because our digital cameras are carefully calibrated to pick up visible light the same way our eyes do, if our eyes were are effective as cameras at capturing those photons, the galaxies to our eye's, would look like the photographs. The photographs are directly engineered after how our eyes pick up and perceive light. This is why they use Red, Green, and Blue pixels to pick up light in a digital camera even tho these are not the primary colors, because the receptors in our eyes pick up Red, Green, and Blue light. They also design the sensor with almost twice as many green pixels than red and blue, because the human eye is *most* sensitive to green light. I will admit there is some deviation to all of this, but my argument is for the most part, *if* our eyes were sensitive enough to see a galaxy like a camera does, it would look very very similar. This is fun fruit for thought. Should keep this one going. Chuck Hards wrote:

You guys mentioned that the colors are there- but you missed my point- that we need instruments to perceive them. To the naked eye, the objects are not bright, are not color saturated. Even if we were close to them, they would appear dim, and the colors would be fleeting, at best. This is well-known and not really debatable.

Colors represent energy levels, and that is the way we perceive the differences in those energy levels. For deep-sky astronomical objects, we generally need large aperture or time exposures to bring the flux level up to the point where we can percieve the colors and see the dim, outer regions of deep-space objects.

It's analagous to looking at an x-ray or image of any other spectral region that is beyond our unassisted vision, either because of wavelength or intensity threshold.

Galaxies do not look like their photos, in real-time, naked-eye views, regardless of viewing distance. Ever. The images are always representational and more analagous to art (or even a sort of intensity map of flux levels) than a "xerox copy" or a daylight snapshot of an everyday scene.

Joe mentioned that some people may perceive tints differently and this has also been documented. We've discussed in this forum before how some humans have additional color receptors in their eyes that allow them to see colors completely hidden from most of us. One English woman with the condition would laugh at her friends who thought they were wearing color-coordinated outfits, but to her eyes, they clearly were not! It took her many years before her wondrous ability was recognized- she sees with a richer color pallete than most of us. There is no doubt that she would see galaxies as being tinted differently than we do.

So, I maintain a "yes and no" attitude on what is "correct" color in deep-sky objects. Certainly a lot of what we think of as correct is based on learned behavior. What we are used to seeing, what NASA and NOAO has spoon-fed us over the decades. There is an established paradigm for these objects and we frame our judgements based on that model. Is it correct in an absolute sense? No, for the reasons outlined above. Is it correct statistically? Is there a portion of the bell curve of color processing that we can assign as having more validity than the extremes? That answer is a *qualified *Yes. _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com

Chuck, I understand better what your saying, and agree. My point was this. The values that we assign to those sensors are assigned to match as close as possible what our brain assigns to them. So, in the hierarchy im trying to create, the electromagnetic spectrum is at the top, it is what it is. Different species, aliens, ect. will "see" it however they will. But, us as human "see" it a specific way that does not vary a lot from one Human to another. Then comes the sensor of the camera. It is designed to replicate as close as possible exactly how our brain "sees" the spectrum as well. So, the camera, being better at picking up and collecting those energy levels, is just an enhanced version of our brains color assignments. Thus, if our eye was as good as a camera, the galaxy would look just like the photo.

I'm not disuputing that just because we can't see a particular wavelength doesn't mean it's not there. You miss my point.

What I am trying to express is that colors exist only in the human mind. It is the way we have evolved to discriminate between photons of different energy levels, or wavelengths.

But, our frame of reference is due largely because we evolved under a "yellow" G-type sun.

What we see as "red", for example, may be perceived by an alien race as their equivalent of "blue", for example. Their visual "window" may be shifted with respect to ours. Like the people I mentioned in a prior post who see colors differently than most of the general population, our "rainbow" is just a psychological manifestation. The "red" we associate with hydrogen-alpha light is only "red" in our brains. It's the color we evolved to discriminate photons at that energy level. It doesn't mean that hydrogen-alpha emissions are perceived as "red" by all organisms with eyes. You can only quantify "red" with respect to the rest of the color palette. "Red" only exists within the framework of human perception.

Here is the real key: *There is no instrinsic value of "red".* At least outside of poetry and prose, lol.

The CMOS chip in your camera records energy levels only, not "colors". Humans have assigned colors to those energy levels based on our own perception, which is the way it is due to evolution (environment), not an absolute expression of what colors are.

You can then see how color balance becomes a matter of balancing the ratios of the wavelengths present in the image with respect to one another. What "color" we assign to those is strictly a matter of psychology, not some universal absolute.

Does this help any? _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com

Chuck, You brought up aliens ;) If cameras did not do an excellent job of reproducing what the "general population" sees, they wouldn't be selling any of them. Your also not correct about "having" to shoot in raw format. You can easily set the the white balance of the camera, shoot a shot of M42 in low resolution JPG mode, and end up with a very nice image that will look very similar to one you would have to tweak out in raw format. The simple compression scripts in the camera *that are designed to create the color pallet our brain sees* work well with no processing. The reason you shoot in raw is to gain more data, and control over that data, and to remove false readout signals such as noise. I think my point still stands. Cameras are designed to create the colors the general population sees, and thus, they capture the same set of colors from space, which would be the colors we would see if our eyes were bigger, and capable of long exposure. ;) I don't know if you have ever seen color in M42 with your eye before, I have. I can also make out the blues and reds in the trifid nebula after a minute or two. The colors the camera are capturing are accurate relative to the general human population. At least as far as consumer grade DSLR's and Point and Shoots go. Chuck Hards wrote:

You don't have to invoke aliens as perceiving colors differently, there are plenty of humans who do it, just not in great numbers compared to the general population. And many terrestrial animals and insects "see" well outside of our visual window. Undoubtedly "colors" correspond to energy levels differently for them, than they do for us.

You wrote "As good as the camera". Let me try and understand what that means. I'm going get picky here so forgive me, David.

That is true if you ignore the fact that the camera (computer, actually, or film emulsion in the old days) builds image intensity over time. In real-time, it is not much better than the eye in the visible part of the spectrum.

The tint and saturation of a particular image is rarely aesthetically pleasing in raw format straight from the camera, apparently, so we need to "re-balance" those attributes with image processing software.

We spend as much or more time manipulating the image after the file (or files) have been acquired and stored. The (astronomical) camera does none of this, it's all done by either a photo technician at the enlarger, or the computer operator if it's a digital image. The individual is then more artist than documentarian, just by nature of the activity itself.

So I stand by my statement that color is still all in the mind, and has no intrinsic qualities at all. "Correct" color is subjective and not objective. Like beauty, it is strictly in the eye of the beholder.

On Wed, Dec 2, 2009 at 2:23 PM, David Rankin <David@rankinstudio.com> wrote:

...

Thus, if our eye was as good as a camera, the galaxy would look just like the photo.

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On Wed, Dec 2, 2009 at 12:28 AM, David Rankin <David@rankinstudio.com>wrote:

The CMOS sensor is not inventing any new colors for these objects, it is simply designed to pick up wavelengths of the electromagnetic spectrum from around the start of UV light, into Infrared light. The CMOS is naturally good at detecting IR light, and has to have a filter put in front of it to block that light for your average end user photographer (I removed this filter to make the camera shoot IR again). You can tweak them a lot, but for the most part, each gas is going to give off its signature light wavelength in the electromagnetic spectrum. Just because we cant see it with our eyes doesn't mean that is not the real color.

David, you've made a pretty good case, but that last sentence is not true. Humans perceive a very narrow part of the spectrum and we have assigned tints and colors according to where a particular wavelength falls in our sensory "window". The spectrum actually extends far beyond what we can detect. Many animals and insects can detect wavelengths far beyond the human range and see colors that we do not. We would see those colors as "black", whereas a moth might see them as something incredibly vivid. So the term "real color" has no meaning in that sense. The human visual perceptive window covers a very small portion of the electromagnetic spectrum dominated by photons. Colors a way for us to distinguish energy levels, and exists only our minds.