Episode I: Stacking Night Sky Images in Adobe Photoshop

[Music] hi this is Joe from Dark Arts astrophotography and welcome to my first ever video tutorial this tutorial will be on the topic of stacking deep sky images using Adobe Photoshop stacking is a very important part of astrophotography as it allows us to take several short exposures and combine them to give the equivalent integration time of taking a much longer exposure when images are stacked pixel data found in each image will be amplified whereas random pixel data which is the digital noise present in Ohio ISO digital images will be reduced the end image the end result rather is an image with more detail and less background noise for Windows the main tool people have been using for years is a free program called deep sky stacker it's a very very powerful image stacking tool it has multiple benefits whereas it will analyze images for quality sort them by quality reject bad images it allows you to add calibration frames which is another topic altogether to reduce noise even further and it's it's just a great tool altogether it was its development was abandoned it's an older 32-bit tools so it's not ideal in you know newer versions of Windows it's still available if you use Windows and you might want to look at using this instead of this method personally I actually kind of like this method here and I found that in some cases I actually get better results stacking only light frames which is the actual pictures and no calibration frames in Photoshop that I do in deep sky stacker I'm not sure why exactly but it seems to work for me so I actually like doing it this way now for Mac users your choices are far more limited when it comes to astrophotography tools I there are no free tools that I'm aware of by all means if there are any that you're aware of post them in the comments below I'm sure it would be a great resource anyone I'm not a Mac user so I don't really know them but there are tools such as picks incite nebulosity available for Mac but they tend to be rather expensive and people likely won't have them and if you can't afford them that's probably a problem but the majority photographers will have Lightroom and Photoshop so this is why we're focusing on this to do our stacking for this tutorial I'm using Lightroom 2015 and Photoshop CC 2017 I know the stacking works and all versions of Photoshop CC I'm not sure if it works in older versions as I've never I'd never used this before starting to use CC a couple of years back so again if you know if it works please post in the comments below I'm sure people would love to know about it if that they can use their older version of Photoshop to do this so this demo will be doing some pre-processing first in Lightroom will be adjusting the RAW images that we shot first removing forgetting adjusting white balance removing any noise reduction or anything before exporting them into Photoshop for the final stacking so we're ready to get started as you can see here I've already imported my photos into Photoshop or sorry into Lightroom I've got 27 exposures I started off with 45 I've removed I shot a total of 45 but I manually filtered out any of the shots that had any start railings clouds blowing through and any other anomalies that would hurt my final quality of my image I kept only the best of my image and I'm left with these 27 so we're going to start the process so first you need to select all your images so ctrl or command a to select all then pick one that's somewhere in the middle that would be representative of all your images and hit the develop module now as you can see on this image you can see the Pleiades cluster you can see some of the nebulosity it's not very bright but you can definitely see it's there and as you zoom in you can see there's quite a bit of background noise here I mean it's not terrible but it's not it's not great this was what will be taken care of by stacking so the first thing we want to do is we want to make sure that all noise reduction and sharpening is disabled so down here let's go down our panel to the detail panel make sure that sharpening is disabled luminance noise reduction is turned off and that it should be and remove all color noise reduction there's a lot of fine detail and contrast and nebulosity and this sharpening and noise reduction can actually alter it you want to try to keep your image as pure as you possibly can so this is why you want to remove all this noise reduction so now we can start with our adjustments the first adjustment we're going to take care of is white balance as you can see this is pretty blue it's partly because it was shot at a fairly cold temperature of 36 50 Kelvin and partly because of the light pollution since this was taken near City so there's a lot of glow in the sky and but we want to try to neutralize this with the white balance as much as possible you could try just doing an auto white balance but in many cases I find it warms it up too much and gives it almost that too much of an orange glow so I actually like to just keep it on as shot and do the manual adjustment in order to do this increase your vibrance and your saturation sliders to 100 as you can see this is now really really blue so at this end of the scale you have complete blue at that end of the scale you a lack of blue completely and you have it all read in green that gives you this orange tint what you want to do is find a spot somewhere in between here where you seem to have a good balance of blue and orange and I'm kind of liking here around 4900 I think that this works out well for this image years will vary this is very very dependent on the conditions at the time you shot the camera you used your white balance setting on your camera my numbers will not be your numbers you really need to experiment with this to find what looks best for you now this looks terrible right now obviously because vibrance and saturation are turned up all the way once you've found a good balance you need to reset these two you can do that by either double-clicking on the label or on the actual slider itself now as you can see this is much more neutral much all that blue in the background is gone but you still have some nice blue details and the stars and in the nebula s'ti around it so good white balance is now complete now we move on to the next step of the processing which is your van getting you can see the fur getting around the edges here but you can really see it in your navigator pane a lot of times adjusting for forgetting you'll actually want to look here instead because this will give you a better representation in your fullscreen way so to adjust vignetting the first step you'll do is you'll increase your contrast go to 100% then down here to your tone curve and go a strong contrast so right now it's very dark so I'm going to increase exposure a little bit there we go now you can see you can really really see the contrast between the dark areas in the vignette and the actual foreground of the image so now we want to adjust this let's go down to our lens correction tab just as an aside here don't use this would actually clean up your vignetting correctly but it will also distort your image a little bit as it tries to do your lens profile correction unless you have absolutely 100% perfect tracking on your mount I would suggest never to do this as it will screw up your stacking so leave this off and we're going to manually adjust the pan getting here so let's try to increase this brightness on the vignette ik obviously the midpoint is not set properly this is going to take a lot on the midpoint maybe a little much are you three again this is another setting where my numbers mean absolutely nothing unless you're using the exact same camera and lens that I am this will mean nothing to you at all you really have to experiment look here and you're especially in your navigator you'll really see the difference to be getting makes adjusting your midpoint that's pretty extreme setting for me on the midpoint but that looks pretty good to me it looks pretty even across the image so I'm going to leave it there so now oh and here also if you have if you find that you have any chromatic aberration around stars often very very bright stars will have a big blue ring around them now's the time to get rid of them with your defringe so the purple hue not so much the green hue but especially purple in my case mine is pretty good the only place there's blue is around the bright blue stars that should have them so I'm going to leave mine okay now in the beginning has been adjusted you want to reset your contrast so on your tone curve you can right click anywhere on the curve and go to reset all and then reset the contrast by double-clicking on it and exposure by double-clicking on it and there you go you have a nicely pre processed image that's nice and neutral in the background and ready to be stacked now that we have this image done we want to apply these settings to the rest of the images in the collection so with them all selected you want to hit your sync button so you can synchronize all these develop settings across all your images hit your sync button make sure to check all so that everything is checked and go synchronize now all your images are ready for stacking and back to the library so now with all the images stacked the next step is to send them to Photoshop by right clicking edit in and going to merge to panorama in Photoshop this doesn't sound very intuitive at first but it really is because the panorama tool in Photoshop will align all the images for you which I'm going to show you in the next step I'm going to pause this for a second here while I do this because this is going to take a couple of minutes and we'll be right back once everything opens up in Photoshop and we're back now in Photoshop as you can see we have now opened the photo merge dialog box this is the exact tool that you would use if you want to create a panorama all the images are already in there yeah I mean you could do this manually you could you could forego the pre-processing in Lightroom completely and just open all your images here and just do this but really I strongly recommend doing the pre-processing in Lightroom because it makes a huge difference on the final process anyway for settings here make sure that your layout is auto and remove the check box from the blend images together you don't want any blending to happen here you just want them to align the different layers each one of these images will be loaded to a different layer and then Photoshop will align them to each other which is what you want and here we go it opens one it opens every image to a separate layer and then it will turn around and eventually just completely align all the images this will take several minutes the more images you have in the stack the longer it will take again I'll pause this and let it do its thing and I'll be back once the stacking err the import is complete and we're back as you can see we have all our images imported two separate layers in photoshop and photoshop has gone through and aligned every single one of these images as can you can see along the edge here by this we'll get rid of my crop tool but just slightly uneven hedging which is just basically stacking the stacking issues as things were being aligned so now we have all our images imported we have our next step is to stack them into a smart object you can do this by selecting the top one by clicking on it scroll down the bottom hold your shift key click that one to select everything right click and go to convert to smart object again this is a process that will take a couple of minutes so we'll again longer depending on how many images you have and the speed of your computer and all that so I'm going to pause the video for until this is done and we'll be right back and the combining of smart object is now complete as you can see all the layers have now been combined into one object which is the smart object now comes the point where we stack make sure that your smart object layer is selected go to your layers menu to smart objects and here down to stack mode and select median this is another one of these processes that takes a little while depending on how many images you have how fast your computer is I have a reasonably fast computer so this doesn't take too long but I've done this on my laptop and regretted having to do it because I basically walked away and came back 20 minutes later and it was still cranking through so this shouldn't take more than about another minute or so in mind I'll pause again and we'll see the results when I get back and I could have gotten away without pausing because it literally ended about two seconds after I hit pause now our image is stacked if we zoom right in we can see that this background has very little noise compared to here in my history I will step back up I'll step back one step you can see what oh that was kind of a bad frame it had some very elongated stars I must have missed that one but that's okay if there's just one once stacked you can see all that background noise has disappeared and the stretched star data which was only in one frame of the image was removed because it was detected as being noise so before stacking and after stacking look how clean that is compared this is really really quite an amazing process and normally people will put dark frames to remove noise and which is a perfectly valid way of doing it up it is kind of the recommended way but this just goes to show you what kind of if you can get from stacking without any kind of calibration frame so now that you've stacked your image it's time to flatten it so now you want to flatten the smart object into a single image on a frame and there we go we have our stacked image so we'll take our crop tool and go and crop those bad edges out so don't we have nothing but it's soups mess that up good data kind of Center that a little bit better and I'm going to crock crop it even a little bit more maybe give it a little bit of rotation just because like that and there we go let's do a little level adjustment here to bring up that bring that black point down there we go we have a nice very clean background and we have the Pleiades cluster and while this is not a processing video I'm just going to give this a little bit of a stretch just so we can see what kind of data that we actually have in this image so I'm going to set my anchor points at 20 20 and 11 11 let's select the edge of this stretch it out for an initial stretch and there we go so from here to here and from then this would be the point where you would start doing your regular post processing which I hope to do in another video sometime in the future so that's it for now I hope that you find this video was informative so it can be about 20 minutes in the length so I hope you liked it if you have any questions or comments by all means post in the comments below hit up my website at dark arts Astro dot CA and I have my blog I have other tutorials I have reviews and come check it out alright so until next time keep those eyes and the lenses pointed up

Channel: Dark Arts Astrophotography

Views: 48,084

Keywords: Astrophotography, astronomy, photography, dark, arts, tutorial, instruction, learning, stacking

Id: ImUxpRkax6I

Length: 20min 33sec (1233 seconds)

Published: Tue Nov 29 2016