Astro Image Processing - Deep Sky Videos

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hi everyone last time we're with Nick Semenuk the astrophotographer we were out in his dome showing you how his telescope worked what equipment he used to capture images of deep space today we want to show you what he does with that data he gets from space how he processes it usually in Photoshop now I should point out this isn't going to be a Photoshop tutorial we're not showing you every step it's just to give you an idea of the sorts of things he does to take that raw material from space and turn it into the amazing pictures we often see from him I would like to show you is actually a an imager took of the Rhine Nebula two or three years back now from the back garden observatory and it's really to show you what can be done to bring our objects of interest within the raw unprocessed data and the Ron nebat is a good example of that because there's some very interesting structure in there so I'll be using photoshop adobe photoshop all we're looking out on the screen is obviously the Orion Nebula itself this area here is called the trapezium you can see the four stars here in this area around he's called the fish's mouth the Ryan neighbor of course is a mission nebula the stars within the neighbor itself of collapsed and formed out of the gas and dust and the kind of foreign very high-energy radiation back into the neighborhood sculpting this incredible three-dimensional shape and it's that what we need to bring out the first procedure we'll use on this is something called a high-pass filter which is kind of sharpening filter initially we just create duplicate image as a separate layer and then we apply the filter to that layer now when you see that on the screen you're probably thinking what hasn't exactly improved the image that much but it is just applying the filter to the top image what we then do is just blend the two together to produce a sharper version so that's with the high-pass filter applied and that's without you might notice that it appears the image is kind of snapping into focus you can see more structural detail around here something else we can do we can use Photoshop Slayers to maybe bring out some of this area around here you can see as the image looks at the moment it's quite dark but I know from experience that the nebula is actually filling all of this area around here it's just the way the image is being shown on the screen I can work specifically on just the outer part of the nebula just using this so-called arrays at all here we're not affecting this partner we want to retain that as it is because that's just showing us all this lovely structural detail but can you see now how magically these outer parts of the neighborhood just beginning to appear and again we can do a direct comparison between what we've actually got on the screen now and how we started what we're doing here course is just working on what we call the luminance data to produce a color image what we have to do of course is use red green and blue filters although the camera itself is black and white and the images we take through the filters are black and white when we combine them in Photoshop it suddenly snaps into color we actually just had to open these up there's three files red blue and green and what we have to do is we had to tell Photoshop to combine them into a three channeled color image it's very straightforward in here we just come over to the channels menu select merge channels we select RGB color and three channels one for each of the colors and here we actually just had to assign the correct image to the correct Channel now this is an image in its rawest state we've just taken this color data we've combined it all together we need to work a little bit on this to get it looking a little bit better the first thing we need to check is the actual color alignment of the stars because these images may have been taken two or three weeks apart if the weather was bad so it may be that the telescope wasn't pointing quite accurately to get them in perfect alignment so what we have to do actually just zoom in and have a look at one of these stars and you can see there that they're not actually in alignment you can see the green one is just shifted slightly the red one is and the blue we select the red Channel what we do now we move the red Channel relative to the other parts of the image can you see how I'm just dragging the red Stiles away so we just put that on there now just do the same thing to the blue Channel there it is you can see it's moving around the green what the green doesn't look too bad as you can see now our stars are nicely in alignment from this point on it becomes very very subjective what you actually do to the final image it's a very personal thing and everybody processes their images in a different way something that will degrade your image when you're working with color is light pollution and that manifests itself as a background glow in the image so we can start to process that quick and dirty way would be to select what's called color balance you have red green and blue on this side they're opposites at the other end of the scale and just at the bottom here we have shadows mid-tones and highlights so if we're working for example on the sky background we need to work with the shadow as part the principle is we switch it to shadows we come up to where the green slider is and because the light pollution is manifesting itself a little bit as green around the edge we just take the green down a little bit as I undo that and redo it you see how the image is shifted more towards a slightly reddish color a lot of people will be quite happy to stick with just a straight RGB image as a color image and when we first started that's how we used to do it as well then a friend of mine suggest an alternative technique called el RGB imaging low luminance red green and blue and the idea behind that is you shoot a deep unfiltered image just to build up the maximum amount of signal that you can during an exposure but what we can actually do now is combine the color layer with the luminance layer and blend the two together it's a simple clicking Photoshop to do that even so once we were aligned now as you see here the end result isn't very pleasing you but this horrible salmon pink color so there's quite a lot of processing that we have to advanced to to actually get the end result it would take too long to do it here and now we don't bore people with the results but what I can do is actually show you what the end result of using these two images was this required probably about an hour's worth of processing and what we're seeing here is this union of color information from one set of filters with a deep unfiltered image which has captured all for example the incredible structure around the trapezium the Orion Nebula becomes very 3-dimensional what you see in these different colors I think it's a sea probably one of my favorite images and both components were taken on fairly poor nights a lot of haze and a lot of dust and stuff like that around and you trying to make this look real or are you just trying to make this look beautiful I'm not sure I understand what you mean by real because what is real you might have 10 images living next door to each other on the same night taking a picture of the Orion Nebula if they're using different filters or different telescopes or different cameras their results will be subtly different and because acquiring the data is only 50% of the job the second 50% is the image processing as we've seen it's a very personal thing and you can you can really put your own stamp on an image and make it your own I'm trying to make it not look real I'm trying to make it look good which isn't the same thing just a quick reminder if you want to see more of Knicks work other than what we show you here on deep sky videos you can check it all out at his website it's CCD land dotnet and also we've got the previous video I know a lot of you probably seen already but there it is you can click on that or underneath that's the video all about his telescope and the equipment he uses to capture the images in the first place
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Channel: DeepSkyVideos
Views: 46,090
Rating: 4.9753084 out of 5
Keywords: astrophotography, photoshop, images, image processing, Adobe Photoshop (Software), astronomy, astronomers, messier, space, galaxies, nebula, nebulae, stars, universe, deepsky, deepskyvideos, deep sky, telescope, Messier, Messier Objects, Messier Catalog, Messier Catalogue, Nik Szymanek
Id: rsj9Td6Dl8I
Channel Id: undefined
Length: 7min 28sec (448 seconds)
Published: Tue Aug 07 2012
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