DeepSkyStacker Tutorial: A Beginners Guide for Astrophotography

as exciting as astrophotography can be when you're actually outside capturing the images of these deep sky objects an equally important part of the process is how you take those images to properly calibrate and stack them to later bring out remarkably faint details of your target in today's video we're going to take a look at a step-by-step guide that'll walk you through how to use deep sky stacker to do just that if you enjoyed this video please like it and subscribe to this channel but most importantly let me know of the programs and settings that work best for you in the comment section below the light flat dark and biased frames that i'm going to be working with in today's video were recently captured of the orion nebula and i'll be sure to tag a video and leave a link in the description below that goes through each step of the process of how to accurately capture them now let's get started by previewing our images and loading them into deep sky stacker so the first thing we're going to want to do is preview the actual files that we captured of our target before we put them into deep sky stacker i've got them loaded up right here into the light flat dark and biased frames that were captured as you can see windows 10 will not open these raw files now there are some extensions that you can download from the windows store to help with this but i've had limited success and those actually working so i would suggest that you google a program that will allow you to open raw files to preview them for free one that came with my canon dslr camera is called digital photo professional four and it's an excellent one that's going to allow us to preview these files right here so the point of this process is to pick out the best frames that we took and get rid of the ones that we don't want in the stacking process now this can be easy to begin with for example i've got my test shots here early on where i took 15 30 45 second and one minute exposures so i already know that those aren't going to work for what i'm doing tonight so i'm going to go ahead and just get rid of those now we're going to go a little deeper and look at the actual files that were captured at around 20 second exposures in iso 400 before we put them into deep sky stacker what you're going to want to look for here is pinpoint stars so we've got the orion nebula right here and we have what look to be fairly sharp stars in the field of view that means that the tracking mount was doing well there wasn't much wobble in the gears or a breeze that came through to maybe throw it off so this is definitely an example of a frame that i would want to keep for this process now i have over 200 frames here and i've gone through and already previewed them i didn't want to make this a two hour video just on previewing the frames but i've got a few examples of ones that i can keep and that i'm going to get rid of just to show you one of the files that i'm going to keep is actually a pretty cool picture here of an airplane i think it was a delta airlines flight going to atlanta georgia traveling past the orion nebula pretty cool image this is one i can keep because deep sky stacker will be able to use other frames to remove the streaks of light that we have here from the airplane and even to satellites that are moving through right here so that's one that's completely fine to keep an example of one that i'm going to get rid of is image file five six two right here so this is one that we're going to want to get rid of because either a breeze came through or the gears shifted in my tracking mount so we see star trails here so this is one that i'm going to want to go ahead and delete and remove from the files another one was image 0 6 0 5 right here and you can see the same thing for this one we've got star trails going on something something definitely happened with the gear for that one so we're going to go and remove that one the same thing for zero six zero six and then there were at least one at the end as well that i think i caught as well yeah this one right here uh not as bad as the others but still throws it off a little bit there are other pieces of software that can allow you to preview these quicker than just having to click on them manually pixencite has a part of its program called blink that allows you to load all of these pictures and basically run them like a video playing them very fast where you can see any wobbles or shifts or change that you may want because you want the the images to be as sharp as they can be for the light frames for stacking them in deep sky stacker in just a few minutes just to do a quick preview as well of our flat frames that we have here these flat frames look good i just like looking at them to make sure there aren't any noticeable differences in their brightness but it looks like the camera settings were set correctly for that dark frames look pretty good as well going through here we can actually open one of them up real quick to show what they actually do so we've got some different cold and dead pixels here and we have the banding effects that are going to be hopefully removed for our final master image from this process kind of neat to see that then we have the bias frames as well to look at here in terms of that in terms of the uh the the bias signal that they're going to be removing from the sensor to help clean up our light frames as well so we've got our light flat dark and biased frames all ready to go to load up into deep sky stacker so let's get to that process i've loaded deep sky stacker onto my computer it is set to default settings so this is exactly how it's going to be for you when you load it up if it's the first time that you've used it we've got a very nice clean interface here where we have kind of the options for registering computing and stacking the images over here we'll be using a number of these throughout this video we have a slider up here that can adjust the brightness of the images and our files will be loaded here as we put them in so let's let's get started the first thing we're going to do in deep sky stacker is load up our light frames that we have again these are the most important part of the process because they're the actual image of the target that you took that night and again let's go to this slider here this won't have any impact on the images just to get a better idea of what we're looking at there with the beautiful orion nebula front and center we're going to go over here and we're going to just work with our light frames for now and we're going to check all at this point i'm going to go ahead and compute these light frames to give us scores for each of them that were taken so the software is going to do kind of an initial process of them to tell us what is in each of these images in terms of what we want to keep and maybe some images that we still might want to get rid of by scoring it in different ways so after you click check all for our 211 light frames we're going to come over here to compute offsets and we're going to let this run for a few minutes depending on your computer for each of these steps this may take minutes or tens of minutes so we're going to speed up the video right now to get onto the next step of the process once we're done computing the offsets of our light frames we have to take a look at what the scores and analysis actually was of deep sky stacker so there are some of these that you're going to want to use and some that you're not one that i have not found helpful is the actual one that's titled score this tends to take a look at the number of stars that are in the frame which seems like it would be something that you would want it to do but actually is something that can be kind of ineffective for it for example if we take a look at this right here this is the highest score of the entire one which you would think hey that must be the best frame but it's actually because it's the image we saw earlier of the airplane going through so the program thought that these streaks of light were stars when in fact it's an airplane so that makes this not a very useful score for us one that is helpful is fwhm which we have right over here this is actually going to look at the size of the stars and can be a good way to pick up star trails that you may have missed from your mount not working properly when you were manually looking at it so this one right here has a score of 3.13 and if we pick a star right here we look at the upper left corner of the screen and that is pretty round it looks good if we go down here to a a f w h m score of 3.59 and go to that same star it's a little less than it was before but probably not enough for me to want to remove it that would probably be pretty picky at that point so i'm going to be keeping all of these even looking at that parameter another important one is sky background this is a great one to look at in terms of cloud coverage even if it's a clear night sometimes you can have some stray clouds that come through that bounce and reflect light pollution that can really change the brightness of the background sky so for this one right here we have a score of 3.68 percent and then when we go down here we have a score of 4.6 and you can definitely see that in these later images orion was getting closer to the horizon more light pollution was coming through from where i live it's a judgment call from you as to when you cut that off i don't think it's a big of enough difference knowing my skies and having seen these pictures in person to get rid of any but if you wanted to cut it off at 4.5 you could do that or 4.25 but you will be losing data that can be stacked down the road but for where i live and my level of light pollution i think i'm going to leave them all just as they are once we've reviewed each of these light frames it's going to be a good idea to go through and pick what we call a reference light frame this is going to be the image that deep sky stacker uses to align and stack every other light frame that we have i'm going to go in here and pick one of the early ones because it's a low level light pollution i know the stars are pinpointing all of these so i'm just going to kind of pick one of these first ones here if we right click on it we go up to use as reference frame and then that's the one that'll be used to align and stack all of the other light frames for our final image so we are good to go with our light frames we have 211 that have been looked at manually by us that have been computed by deep sky stacker analyzed and i'm very happy with the results for each and every one of these so at this point we're going to go up and we're going to add our dark frames to this program our flat frames and our bias frames so now we have everything that we captured for the entire night checked and ready to go in deep sky stacker 211 light frames 150 dark frames 73 flat frames and 75 bias frames now we have to get to the process of making decisions on how to actually register and stack each of these different types of frames so let's go up here to register checked pictures now all of these settings are default like i said earlier for the actual program as it was installed on my computer since i've manually gone through and looked at each of these i'm actually going to change this to 100 percent keep everything else as it is here keep the star detection threshold at 10 percent all of this is looking just fine we'll then go and click on stacking parameters this is when we get into the fine details of what settings do we want to use for this program since i have selected a light frame as a reference i'm going to pick standard mode for this right here an option that you may want to dabble in is drizzle i sometimes will use two times drizzle this is actually a a process that was developed for the hubble space telescope and it can be helpful if your images are under sampled a sign that you have an under sampled images sometimes you will get square looking pixels when you zoom in on your stars the imaging setup that i'm using with my sensor camera lens is is not one that's under sampled so two times drizzle will only increase the file size of the image and it's not something that's going to benefit me right now but it may be something you want to experiment with if you are shooting under sampled or if you're not sure you could click on it and see what happens but that's not a setting i normally use everything else looks good there we're then going to go into the light frames and we've got some different options here as to what we can use let's start up here with average for the average setting this is going to average all of the frames together but from that it's going to keep things like streaks of planes and satellites and we definitely want to get rid of those so averaging our frames is not going to be something we're going to want to do median is one that does exclude satellites and airplanes but you lose faint differences in brightness you can almost get sometimes a stair-stepping effect where it's not a smooth gradient from one brightness to another but kind of like it looks blocky almost so median isn't one we're going to want to use kappa sigma is the one that i traditionally use for this software and it's a wonderful mix of average and median and it really is the best of both worlds so you get the precision of brightness and you also get the clipping that takes out bright extreme pixels that stand out such as the streaks of an airplane or a satellite moving through so kappa sigma is what i almost always go with sometimes i'll try out median kappa sigma but the image results can be a little soft at times it's not quite as sharp of an image as kappa sigma in terms of our dark flat and bias frames um a book i read on astrophotography a few years ago suggested median kappa sigma clipping so that's what i use for that same thing for flat and same thing for bias when we get over here to alignment i'm going to keep that on automatic keep all of these settings the same and it's going to be saving to a tiff file which will give us a lot of data to work with for our post processing so all of this is looking good and ready to go from here we can double check what we've just selected by just taking a look at what recommended settings are for this software everything's looking good here i found that i typically don't need to set this point to zero everything's looking green good for our light frames all right so the settings that we picked uh were the ones that were pretty much recommended by the software anyway so that aligns with the book i had read on astrophotography and works well so from here we're going to click ok and now we have a final preview of what exactly the software is going to do everything is looking great so let's go down here and click ok so at this point the software is going to run it's going to add the offsets it's going to calibrate it's going to stack and it's going to take a long time depending on how many frames you have and how fast your computer is this could take a few minutes this could take 30 minutes 45 minutes an hour it just depends on what you're working with so let's fast forward through this process and get to our finished result and after about 35 minutes we have our final stacked and calibrated image of the orion nebula with deep sky stacker we were able to combine our light frames to over one hour's worth of data which will bring out fine details of our object by improving the signal-to-noise ratio we also used flat bias and dark frames to further improve our image by removing imperfections from the lens and sensor of our camera it's understandable if your first reaction to this final stacked image is one of disappointment when i first started using deep sky stacker i remember wondering why the final image looked darker than my light frames and was surprised that faint details and colors weren't already showing up those details are in this image but must be brought out of it using additional software i've got a video coming out that goes over how to load this file into a program called pixensight so that we can stretch and enhance it to bring out the features and colors we all want to see in our astrophotography i'll be sure to tag it and leave a link to that video in the description below i hope you found this video helpful if you have any questions or suggestions on how to use deep sky stacker please be sure to let me know in the comments section below thank you all so much for your continued support and clear skies from late night astronomy

Channel: Late Night Astronomy

Views: 6,451

Keywords: deepskystacker, how to use deepskystacker, deepskystacker tutorial, deep sky stacker, deepskystacker astrophotography, what is deepskystacker, how to download deepskystacker, how to stack images, how to stack pictures, how to stack for astrophotography, astrophotography tutorial, calibration frames, how to stack light frames, how to stack flat frames, how to stack dark frames, how to stack bias frames, deep sky stacker tutorial, how to use deep sky stacker, astronomy

Id: CBNCuXB9Gx4

Length: 20min 20sec (1220 seconds)

Published: Sat Apr 10 2021