Cone Nebula Color Question

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spacerings

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The NASA writeup for this says: "Ultraviolet light heats the edges of the dark cloud, releasing gas into the relatively empty region of surrounding space. There, additional ultraviolet radiation causes the hydrogen gas to glow, which produces the red halo of light seen around the pillar.<br /><br />Then it further explains later: "The color image is constructed from three separate images taken in blue, near-infrared, and hydrogen-alpha filters."<br /><br />So, have they chosen to make the hydrogen look red or is it glowing red in visible light?<br /><br />Cone Nebula: http://store.spaceimages.com/noname16.html
 
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tfwthom

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This is a kind of astrophotography question more then anything else.<br /><br />Color in photographs is limited to red, green, blue. (either film or CCD) In CCD because of the filters used, on flim because of the layering.<br /><br />Why film is going away for astrophotography is because Kodak and the rest are trying to help photographers do away with "redeye" and are killling the films sensitive to red. <div class="Discussion_UserSignature"> <font size="1" color="#3366ff">www.siriuslookers.org</font> </div>
 
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tfwthom

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Did you get an advanced copy of the March Sky & Telescope?<br /><br />Page 8 has a piece on astrophotos.<br /><br />The Camera Always Lies by Richard Fienberg.<br /><br />"One of the problems with truisms is that they're not always true. So it is with this one: "The camera never lies." Whoever came up with it surely wasn't an astronomer. Astrophotos always lie.<br /><br />etc.......<br /><br />"Virtually every astrophoto is a fake in one way or another. But that's a good thing - usually."<br /><br />Pick up a copy to read more............<br /><br /> <div class="Discussion_UserSignature"> <font size="1" color="#3366ff">www.siriuslookers.org</font> </div>
 
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Saiph

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...I think I might just pick one of those up. <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>
 
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tfwthom

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Another quote:<br /><br />"And what about color? In the eyepiece of a small telescope, nebulae and galaxies look dim and gray. But photographed through the same optics, those same nebulae and galaxies can erupt in a kaleidiscope of blues and reds - or maybe greens, oranges, and purples, depending on what filters you shoot through and how you combine and display the colors in your computer. Real galaxies aren't green, orange, and purple.<br /><br />Still, astrophotography has been very good to astronomy, even if the images aren't always "real." <br /><br /><br /><br />Actually I love the picture they have with Saturn's rings around Mars.<br /><br />Quote:<br /><br />"But everyone would agree that putting Saturn's rings around Mars, as done here, crosses the line from enhancement to fakery." <div class="Discussion_UserSignature"> <font size="1" color="#3366ff">www.siriuslookers.org</font> </div>
 
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