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Welcome my name is Doug Hubbell and today we are going to talk about DeepSkyStacker.
You can find this very easily by doing a simple search for DeepSkyStacker as one word. What
I wanted to do is show you a little bit about this freeware software and get you started.
It's pretty easy to use. Some of the questions people have when they first get started, what
bias frames? What are darks frames? What are flat frames? What do all these things mean
to me as I'm trying to make an astrophotography image? The best thing to do on this website
is I like this area where it says "How to create better images". If you click on there,
and you kind of scroll down through here you can see some very good illustrations on why
we combine, it has an image right here you hold your mouse over it, and it's one image,
then goes to two images, you can see that as you start stacking the images the image
quality becomes much, much better. And there's a certain point where you start to get diminished
returns. Between about 16 -- 20 images, that's a good set of images. Now continue on through
this, right here it's talking about the calibration, it says how to use dark, flat, and bias frames.
When you look through here, it has another example here; it starts off with 32 frames
with no calibration. As you go through it shows that the same image with 32 frames and
20 darks, 20 flats, and 20 biases. Using these frames you can see it really makes a big difference,
and I highly recommend coming to this website, downloading the software, and click on "how
to create better images". It's a very informative read and you can get all kinds of information
on how the things work in the deepskystacker program.
So let's get started with the actual program. I have here, I've already preloaded some of
my image files, and using deepskystacker, very easy, it goes through the steps right
here, One open picture files, two open your dark files, open your flat files, I don't
use the dark flat files, but I use the bias, so I use three of the calibration files there.
Then what you do is you say check all, o before I do that, let me show you something here.
I already ran these image through but what it does is gives you a score and it will do
this all automatically for you when you run it through there, it scores the HIGHEST image,
and the way it scores the highest image is it scores it under the FWHM, that's Full Width
at Half Maximum. And it also counts the number of stars too. So in this particular example
on this one image I have here, it has 282 stars that it saw there. And it's got a FWHM
of 2.64, Now the worst image I have on this group, comes down to 2.95, BTW the FWHM the
lower the number the better. And it only sees 185 starts in this particular image. One thing
that would be really good to do is check the raw fits DDP settings, you click on that and
if you're using a mono chrome 16 fits or RAW files DSLR or color CCD camera, you need to
define that, you need to go to here and check that and then what it does it shows you the
Bayer pattern. You'll have to select the correct Bayer pattern for your particular camera.
It has quite a few listed inside here. You can select out and those so it makes it the
correct color when it comes out. This particular image I'm working with right now is a mono
chrome image so I'll just leave that unchecked. But I wanted you to aware of where to find
these settings if you are taking RAW or taking images Fits images in the RAW format. So to
get started with the stacking process, what you do, you go down through the files here,
then you say CHECK ALL. You'll notice that it checks all of the images and then what
you do after you check all you say register checked pictures. It will come up it will
give you some suggestions you can pretty much use all of their default settings. One thing
you can do right here, if your image is kind of weak on stars, it doesn't have many stars,
you can do this, hit, compute number of detected stars, and what it will do is will go through
it. And it found 288 stars. Now that's a good number to have, if you find something like
only 10 or 11 stars then you might need to bump it up a little bit, take this slider
and if you slide it over the left and you say compute again. What it should do is come
up with a higher number of stars. I would say if you can get stars of at least 100.
Then you'll be pretty good, but some images you might find have a very few stars in it.
I like to use about 10%. Getting back to here, what you can do here is you can just go to
these recommended settings and can kind of see what it's suggesting to use. I highly
recommend Sigma Clipping as the combination method for all of your images. Now Sigma Clipping
basically requires 15 images or more. Use Sigma Clipping whenever possible. And for
your bias and dark frames you can just use the median method of combining.
The stacking parameters if you'd like you can go inside here and can play around with
some of these settings. There is the mosaic mode, if you would like to create an image
that has several different frames that are offset. Standard mode is usually what I use.
After you've kind of browsed you can use the default settings like I'm using for the light
frames and Kappa Sigma Clipping is what I'm using.
Then after that you just say ok. It will come up and it will give you a prompt and it will
tell you what it's going to be doing, you kind of review if you'd like, tells you the
method, and then if you want to change anything you can use these buttons and change it again.
Just say ok, what it will do, it will go through, and stack all of these images. The Sigma Clipping
method take the longest time to run, so go off, have a cup of coffee, come back in a
few, and it will be done. After DeepSkyStacker get finished stacking
the image, you'll see this output that doesn't look too enticing, but the thing is that what
it does is it stacks the frames for you, and it will automatically put it in a TIFF file
format for you. So you can do some post processing. One of the things that DeepSkyStacker tells
you on their website, is it's not a post processing software, you do have to take into Photoshop
or some other processing software after you're finished stacking your image.
If this is your first time watching I'd like you to subscribe. I publish two astrophotography
videos on the first and fifteenth of every month. Thanks for watching and I hope to see
you soon!