nice attempts, fellas!
they seem to indicate the 3 main stars have 3 different colours...! is this really the case or simply due to colour corruption from the processing ?
Can you salvage this image??
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Airconvent
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The Rho Ophiuchi nebula clouds is the more colourful area in the sky. They really are the colours of the clouds, though not the stars.
See comparison image: http://antwrp.gsfc.nasa.gov/apod/ap040809.html
http://antwrp.gsfc.nasa.gov/apod/ap040509.html:
Explanation: Why is the sky near Antares and Rho Ophiuchi so colorful? The colors result from a mixture of objects and processes. Fine dust illuminated from the front by starlight produces blue reflection nebulae. Gaseous clouds whose atoms are excited by ultraviolet starlight produce reddish emission nebulae. Backlit dust clouds block starlight and so appear dark. Antares, a red supergiant and one of the brighter stars in the night sky, lights up the yellow-red clouds on the upper left. Rho Ophiuchi lies at the center of the blue nebula on the right. The distant globular cluster M4 is visible just below Antares, and to the left of the red cloud engulfing Sigma Scorpii. These star clouds are even more colorful than humans can see, emitting light across the electromagnetic spectrum.
See comparison image: http://antwrp.gsfc.nasa.gov/apod/ap040809.html
http://antwrp.gsfc.nasa.gov/apod/ap040509.html:
Explanation: Why is the sky near Antares and Rho Ophiuchi so colorful? The colors result from a mixture of objects and processes. Fine dust illuminated from the front by starlight produces blue reflection nebulae. Gaseous clouds whose atoms are excited by ultraviolet starlight produce reddish emission nebulae. Backlit dust clouds block starlight and so appear dark. Antares, a red supergiant and one of the brighter stars in the night sky, lights up the yellow-red clouds on the upper left. Rho Ophiuchi lies at the center of the blue nebula on the right. The distant globular cluster M4 is visible just below Antares, and to the left of the red cloud engulfing Sigma Scorpii. These star clouds are even more colorful than humans can see, emitting light across the electromagnetic spectrum.
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zong
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This was my attempt, done in photoshop by only adjusting color levels.
The picture sacrificed some background stars near the top left and top right, and shows the rough region of nebulosity around the brighter stars, while retaining the blackness of the "background".
I found from the color levels that the stars were really captured in different colours.. I'm not sure if they are really the colours of the stars, but my gut feeling tells me they are. Can't explain why, though.
The picture sacrificed some background stars near the top left and top right, and shows the rough region of nebulosity around the brighter stars, while retaining the blackness of the "background".
I found from the color levels that the stars were really captured in different colours.. I'm not sure if they are really the colours of the stars, but my gut feeling tells me they are. Can't explain why, though.
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Photoshop Elements.ALPiNe wrote:Hi blurlock,
Which imaging software did you use? Registax? The stars in the background still managed to retain their natural look somehow. Really makes the nebula stand out. Nice!
Cheers,
:cheers:
- ALPiNe
But which picture are you talking about? Some I use levelling, some I reduce highlight and increase shadows, some I does layering.
haha....that is an artifact on the negative....something like a scratch...sigh.
anyway, more about the image: it is actually a film image but cannot remember what film was used. But it should be Ektarchrome 200 which is unfortunately no longer available in Singapore. The Rho Ophiu. region is known for its colour yet very faint nebula. So for a film image, we had to expose for almost 1.5 hours even using a fast lens, which in this case was a Nikon 180mmED at f2.8 in Batu Layar. This is actually taken together with MikeMathews collaboratively. However, albeit being a fast lens, it also exhibited vignetting effects, that's why starfinder thought this was the case, likewise with Chris as well. And more so especially with exposures this long, in fact the longest we have ever tried. We have tried shorter exposures using the same lens and film, but the nebulae will just not "come out" as much. In the raw image, as you can see, there was clearly a washed out effect at the center which eroded the colours there as well. Thus it is a tough image to process espcially when one has to consider how to remove the vignetting effectively, and at the same time, preserve and bring out the star colours at the same time. Nevertheless, astrophotographers would like to image this region for its varied colours and the fact that there is dark nebulae present as well! sort of an "all-in-one" thing! ;P
anyway, more about the image: it is actually a film image but cannot remember what film was used. But it should be Ektarchrome 200 which is unfortunately no longer available in Singapore. The Rho Ophiu. region is known for its colour yet very faint nebula. So for a film image, we had to expose for almost 1.5 hours even using a fast lens, which in this case was a Nikon 180mmED at f2.8 in Batu Layar. This is actually taken together with MikeMathews collaboratively. However, albeit being a fast lens, it also exhibited vignetting effects, that's why starfinder thought this was the case, likewise with Chris as well. And more so especially with exposures this long, in fact the longest we have ever tried. We have tried shorter exposures using the same lens and film, but the nebulae will just not "come out" as much. In the raw image, as you can see, there was clearly a washed out effect at the center which eroded the colours there as well. Thus it is a tough image to process espcially when one has to consider how to remove the vignetting effectively, and at the same time, preserve and bring out the star colours at the same time. Nevertheless, astrophotographers would like to image this region for its varied colours and the fact that there is dark nebulae present as well! sort of an "all-in-one" thing! ;P
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Airconvent
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how did process this image?Ah .... film image ..... no wonder there are so much details. I was wondering what CCD / Digtial Camera you used that can record so much. But if it is film image, I should say it is possible for it to record. You can record more if you use a negative rather then a slide film.rcj wrote:haha....that is an artifact on the negative....something like a scratch...sigh.
anyway, more about the image: it is actually a film image but cannot remember what film was used. But it should be Ektarchrome 200 which is unfortunately no longer available in Singapore. The Rho Ophiu. region is known for its colour yet very faint nebula. So for a film image, we had to expose for almost 1.5 hours even using a fast lens, which in this case was a Nikon 180mmED at f2.8 in Batu Layar. This is actually taken together with MikeMathews collaboratively. However, albeit being a fast lens, it also exhibited vignetting effects, that's why starfinder thought this was the case, likewise with Chris as well. And more so especially with exposures this long, in fact the longest we have ever tried. We have tried shorter exposures using the same lens and film, but the nebulae will just not "come out" as much. In the raw image, as you can see, there was clearly a washed out effect at the center which eroded the colours there as well. Thus it is a tough image to process espcially when one has to consider how to remove the vignetting effectively, and at the same time, preserve and bring out the star colours at the same time. Nevertheless, astrophotographers would like to image this region for its varied colours and the fact that there is dark nebulae present as well! sort of an "all-in-one" thing! ;P
Ektachrome E200 is still on sale in Singapore, if I remember correctly. However, Velva is a good alternative if you can't find Ektachrome. You should try to capture it into negative next time.
hi blurblock (name?),
yes perhaps it could be recorded using negative, but as of now, there are no balanced negative to use with senstive emission response and yet low enough grain, that's probably why we decided to go for Ektarchrome 200 which is at the same time pushable by two stops if required. Also, the toe characteristic of the negative has to be short enough so that we can start recording the nebulosity at a much earlier time. Velvia has poor reciprocity characteristic. Am looking for SHQ100 if anyone knows. Where did you find the E200 in SIngapore, please share with us.
yes perhaps it could be recorded using negative, but as of now, there are no balanced negative to use with senstive emission response and yet low enough grain, that's probably why we decided to go for Ektarchrome 200 which is at the same time pushable by two stops if required. Also, the toe characteristic of the negative has to be short enough so that we can start recording the nebulosity at a much earlier time. Velvia has poor reciprocity characteristic. Am looking for SHQ100 if anyone knows. Where did you find the E200 in SIngapore, please share with us.