All language subtitles for [English] How to process GALAXIES with the latest in FREE SOFTWARE [DownSub.com]

This video is sponsored by Squarespace. Welcome
back! My name is Nico Carver and in last week's

episode we covered how to capture M101, the
Pinwheel Galaxy, with used, inexpensive gear and

in this week's episode we're going to take that
data captured last week and process it with free,

open-source software, specifically these four
programs: Siril, GraXpert, Starnet, and the GNU

Image Manipulation Program. I promised I'd show
how to install these programs but I've decided to

put that as an addendum at the end of the video so
if you do need installation help you can just skip

to the addendum appropriate to your operating
system whether it's Mac or Windows. Here's an

overview of what I'll be covering and in what
order. I won't bore you by reading this out but

for people that do want a summary overview you can
pause the video right here to read through this.

Okay the first step is I've looked at my images
in playback mode on the camera and figured out

the ranges of my light frames, my dark frames,
my bias, and my flats and I've noted those ranges

down now I'm ready to take out the SD card from
my camera and insert it into my laptop here or if

you don't have an SD card slot on your computer
or laptop then you'd need an SD card reader for

this step or connect your DSLR with a USB cable
in any case once you've put the SD card into your

computer you should see some kind of popup or on
Mac it will just appear on your desktop here and

if I double click that and then go into this DCIM
folder uh ignore this stuff uh I've used this for

different camera systems but anyways here's all
of the pictures I took on the Canon T7 and since

I've already noted down the ranges I can now
start selecting these and transferring them to

my computer um however let's talk about computer
hard drive space because if I look at my computer

hard drive here I'm just going to click get info
you can see that I have it's a 1 TB drive and I

have about 350 GB available now that might be
enough but I'm not sure because I took about

500 pictures and the way that serial works the
program that we're going to be using it uses way

more space on your hard drive during processing
um and then you can delete those pictures that

it creates later but but you need a lot of space
on an SSD for serial to work correctly so just to

be safe instead of putting this these pictures
just on my internal SSD I'm going to connect an

external SSD which has more free space this one
has over 3 terabytes available so that should be

plenty so what I'm going to do is I'm going to
open up this external SSD and I'm going to make

a new folder on Mac or Windows you can just do
that by right-clicking and choosing new folder

and I'm going to call this M101 that's the
uh designator Messier 101 for the pinwheel

galaxy and then inside that folder
I'm going to make four other folders

four subfolders one called lights one called
darks one called flats and one called biases

and this is the hierarchy that serial expects
if you use the scripts for pre-processing which

is what I'm going to be doing and showing
to in this tutorial okay then it's just a

matter of going here on the SD card finding
the ranges and transferring them to the SSD

and you can either do that by selecting and
pressing control-C or command-C on Mac and

then pasting control-V or command-V on Mac or
you can drag and drop from one window to the

other okay now with everything all the
lights biases darks flats all copied over

um I can go ahead and eject my SD card
and so I'm going to start with Siril

you can see I am on the latest version as
of recording which is 1.4 beta 2 and we're

going to do two things right at the start here
we're going to click on this blue home button

right up here which will change our current
working directory you can see currently my

current working directory is my desktop but
I want to change it to my external SSD so

I'm going to click on other locations go into
the computer go into the volumes and there it

is x10 Pro and then M101 okay so when you get to
your working directory you should see these four

folders that we created and then go ahead and
click open and then up here at the top of the

interface you'll see that it lists your working
directory so for mine it's volumes X10 Pro M101

okay so that's always the first step before
you use the script you have to tell it where

your data in those four folders lives then
we can go into the scripts and this new

uh script dropdown is a little different than in
past versions there's now Python scripts which are

as it says Python scripts things written in Python
um within serial and there's only one right now in

there by default the catalog installer but there's
many other people currently writing Python scripts

that will work with Siril um so this is a cool new
way for any kind of developer just to extend the

functionality of serial through Python scripts and
then there is the standard serial scripts all of

these ones except for RGB composition have to do
with pre-processing your data so if you don't use

the scripts you can instead go through these tabs
right over here calibration registration stacking

but what the scripts do is they take care of all
of that for you um so uh but they of course then

make some assumptions about how you want to
do the pre-processing okay anyways um there

are some new scripts like this Bayer Drizzle
I'm not going to use that here since I didn't

uh guide and dither and things like that that
would be required for drizzling and so I'm not

going to go into that right now but I'm just going
to use the standard one uh OSC pre-processing

and oneshot color OSC is appropriate for anytime
you're using a DSLR or mirrorless anytime you're

using a camera that's not a mono camera you'll
use one of these OSC scripts these ones are for

if you use narrowand filters so since we didn't
use any filters we used just a normal stock DSLR

we're going to do this one OSC pre-processing so
to start it all you have to do is just click on

it and you might get a popup here saying like
something about scripts are experimental or

or don't uh trust all scripts or something like
that if you get that you can just click okay I've

already dismissed it before so that's why I didn't
get it um but as you can see now it's just going

really quickly through all of the pre-processing
it creates uh calibration masters then it uh

calibrates your lights using those masters
then it debeayers your light frames meaning

um actually interpolates them to make them full
color images then it registers your light frames

so you that's why you need those round in-focus
stars because it's using star patterns to do the

registration so that they're all aligned then once
they're all aligned it can actually stack them so

that's the mathematical averaging and it can throw
out outliers like satellite trails and things like

that um but it also of course greatly improves the
signal to noise ratio of your images which lets

you stretch them um much brighter and actually
see these dim objects that we've captured so I'm

just going to let this go and when it's done we'll
catch back up okay and I just finished stacking it

took about 17 minutes to calibrate and register
and stack about 500 lights from a DSLR and this

is just on a uh fairly new Mac laptop but nothing
special in terms of computer power but I would say

as I've said many times before you really want to
be doing this as on an SSD if you're doing it on

a spinning disc drive like a normal hard drive
um it takes way way longer like hours compared

to minutes uh the the really thing that speeds it
up is working on an SSD once it finishes it'll say

script execution finished successfully but nothing
opens up here automatically we do have to click

on open and then here in our working directory
you can see there's two new folders masters and

process and then a result um and then the result
will be underscore and then the total time of what

it stacked so this stacked 9,900 seconds so that
would be 165 minutes so almost 3 hours of data

so I'm going to go ahead and open up that result
and this is what it looks like um but actually

while I was talking about that those folders
I wanted to mention one thing before we move

on these masters if you ever you know want to
calibrate manually without the script you might

want to hang on to like your master bias and uh
this is also a good time just to look at your

master calibration frames and see if there if you
see anything wrong with them um like banding in

the flat or just weird issues um it can be good to
save these but the process folder I almost always

delete it's it's going to be really really huge
because it's full of all the intermediary files

that serial creates and just to give you an idea
of how big it is my original lights folder was 16

gigabytes of data this process folder ballooned
to 320 GB of data so um over 10 times what we

started with even if you include the calibration
frames it's over 10 times bigger um and we don't

need it so what I always try to remember to do is
at this point delete it so I'm just going to move

it to my trash and then empty my trash to free
up that hard drive space so back to the result

um this is being shown in what's called a linear
space if you look down here at the bottom of the

interface um it says linear right there and that's
uh good there's certain things that we want to

do to the picture while it's still linear but you
can't really see the galaxy at all in this linear

mode so we're going to change the view mode
to auto stretch just by clicking on the word

linear down here at the bottom and change it to
auto stretch and now you can see the galaxy you

also see a lot of noise which don't be alarmed by
we're going to manage the noise through processing

but it's actually good to be able to see this
noise because uh you can see that I didn't very

carefully keep the galaxy centered the whole
time I was tracking it so there's some parts of

the image that are noisier than others you can see
there's a big band down here at the bottom and on

the left i mean on the right and at the top where
these sections didn't get as much stacking as the

center part so I would definitely want to crop
those off um and you can just see any issues that

are maybe here in the data with it stretched this
brightly but don't worry too much about its like

color or appearance at this point because we're
going to do a lot of different things to it um but

it gives you a a good sort of first sense of what
what you've captured so you can see there there's

a lot of um that doesn't the galaxy itself doesn't
look very noisy even if we're seeing a lot of

noise out here in the sky the galaxy itself looks
like we have a lot of signal to work with which

is great um even in these outer outer arms we can
see there's they're starting to come in and in the

the brighter central part it's definitely bright
enough now in this auto stretch we're not seeing

a whole lot of color variation in the galaxy it
just sort of has this bluish white tone to it but

um we can tease out the color later so don't
worry about that either okay anyways uh so that's

the auto stretch. We're going to move actually
right into GraXpert there is now in serial 1.4

this ability to use GraXpert right within serial
now um when you open that though I want to point

out that it gives you this deprecation notice
and says this interface is not what it's going

to be in future versions instead it's going to be
a Python script so I'm actually not going to show

that this interface in my video i know it exists
but um I'm going to show GraXpert as a standalone

program because I don't want this video to get
confusing in the future okay so we're going to

go to GraXpert Standalone but before we do there's
one thing I want to measure in this image because

we need this one piece of information in order
to accurately do something in GraXpert called

deconvolution which you can think of as basically
just undoing blur in your image like there's blur

from the atmosphere and different things and
deconvolution takes out some of that blur

so it's it's uh very mathematical but we need to
know the average size of the stars in the image

to do deconvolution as correctly as possible so
uh there's two things we have to do to get that

number the first is we have to plate solve our
image meaning figure out exactly the scale of

uh the image and where it is in the sky so we're
going to go to tools astrometry image plate solver

and depending on your gear this might be filled in
for for me it's not very filled in so uh I'm going

to go ahead and fill it in so I'm going to type
in my object name up here in the little search

box M101 click find it finds the coordinates I'm
going to type in my focal length i was using a 300

mm focal length lens and it actually did pull the
pixel size correctly pretty much uh for my camera

it's actually more accurately 3.72 and you can
just Google that uh pixel size your camera name

okay and then I'll go ahead and click okay and
it plate solves the image quite quickly you can

see down here in the console uh it calculated
the focal length to be 298 mm focal length and

it gave me um some center coordinates here okay
then next we can go to the image processing menu

up here at the top go down to star processing and
we don't actually want to click on any of these

four options we want to click on this little gear
icon and this will bring up the dynamic PSF window

um and dynamic PSF PSF is point spread function
so it's going to calculate uh data about all of

these stars so to do that we're going to go ahead
and uh click this detect stars button it finds all

the stars it gives you like their position their
exact right ascension and declination meaning like

their uh celestial coordinates and then the one
we're interested in is uh this one the full width

half maximum and so we can actually get a nice
average of all the PSFs um by clicking this little

uh epsilon character down here okay and that tells
us the average star data okay so full width half

maximum x 12.4 arcsec full width half maximum y
9.4 arcsec so let's just say we'll pick a value

in the middle of that uh so let's say 11 so we'll
say that our average uh full width half maximum

the average size of our stars in this image is 11
arcseconds all right so you can if you don't want

to see all these little detections of the stars
you can click this delete button right here that

will just get rid of this display you can close
out of that but actually we can now close out of

serial uh completely all you have to do is just
write down that number uh the average full width

half maximum for us it was 11 arcsec so I'm going
to go ahead and quit out of serial and open up

graXpert and it warns me that this is a
beta release of GraXpert which we know

um it will eventually become an official release
but so far uh they haven't gotten to that yet so

this is a release candidate you can see that
up here RC2 um but the reason I want to use it

is because it includes deconvolution which we're
going to use on this image so go ahead and click

load image and then uh open up your result right
here okay and it opens up in graXpert um normally

I would go down here to this display thing and
make this brighter but um I think on the Mac there

might be a bug with this because when I tried
earlier it uh made the program unresponsive so

I'm just going to leave it at 10% background but
I am going to crop so we'll just follow along on

the left hand side here I'm going to open up the
next uh thing here which is crop and I'm going to

crop pretty far in on the galaxy of course we saw
earlier how there were major parts along the top

bottom and right that were noisier than the rest
of the image just because of my imprecise tracking

so you may be able to keep more of your image
than me but I don't want that those noisy parts

to interfere with um the other parts of this
process so I'm going to get rid of all that

stuff and I'm going to do a fairly widescreen kind
of image because that will look good for YouTube

of course so I think that looks good so I'm going
to go ahead and click apply crop and of course

the nice thing with cropping is it also makes the
galaxy appear bigger on your screen we could crop

in even further but I think there's a limit where
it's like if you crop in too far on something

you'll start seeing that you don't really have
the detail to support it so I think uh this looks

nice I'm going to click on background extraction
i wouldn't say this image really needs background

extraction because I shot it fairly high in the
sky and there doesn't seem to be any kind of light

pollution gradient here so we could just skip it
but I'm going to go ahead and use just to show

you view I'm going to use the AI model and I'm
going to turn up smoothing quite a bit because

I don't want it to overshoot on calculating the
background and take away actually signal in the

picture so I'm going to turn the smoothing up
to 0.9 if you had a complicated gradient in

your picture you might want to turn the smoothing
down and it actually did a little bit of something

there that I think looks pretty good so here is
the original there is the gradient corrected i

don't know if you can see that on YouTube there's
the background i mean not much going on there but

maybe just a little bit of uh brighter on
this side okay let's go on to deconvolution

if you don't yet have these AI models set up I
just picked the latest on each one here under

advanced and then the first time you run these it
will ask do you want to download the AI model and

you just say yes and that takes a little while
the other thing I will note is I believe on

Mac and Windows 10 I would uncheck this enable
hardware acceleration because I think there's

issues with it both on Mac and Windows 10 so what
this normally would do AI hardware acceleration is

use your GPU for the AI tasks but I think there's
a bug with it right now so I would turn it off

so I'm going to go ahead and close that okay and
then you have two sliders deconvolution strength

and image full width half maximum in pixels
okay and so this gets a little complicated but

um we need to figure out our image scale so we can
do that with any number of uh calculators online

I'm just using the one here at Astronomy Tools
under their CCD calculators and we know our pixel

size with the Canon T7 is 3.72 and our telescope
focal length is 300 so that gives us a resolution

of 2.56 arcseconds per pixel so remember our full
width half maximum the average width of the stars

in arcseconds that we calculated using serial
was 11 arcsec so now we want to convert that

to a pixel value and we have our resolution here
of 2.56 arcsec per pixel so then we can just do

the simple math of 11 / 2.56 to get our average
uh full width half maximum in pixels which is

4.3 so now we just plug that into GraXpert right
here where it says image full width F maximum in

pixels 4.3 okay and then the other slider here
is deconvolution strength i think the default

is 0.5 and so if you want a stronger uh result
you make it higher if you want a less strong

result you make this lower I'm going to do just
a little bit above the uh the default so I'll do

0.6 and we'll give that a try okay and
zoomed out like this I don't know if I

see much difference but usually the the difference
is in the details you really have to look at the

uh galaxy up close and I think I can see
that it's sharper but then the really good

way to tell is you go up here to where it says
deconvolved object only and switching back and

forth between gradient corrected and deconvolved
and you should see more details here in the core

if you see weird artifacts uh like like little
wormy stuff that you don't expect then you want

to turn down the deconvolution strength or maybe
turn up the image full width half maximum so you

can play around with it but every time you run
it it does take a while so uh just keep that in

mind trying to get these values somewhat correct
right away is probably preferable okay next up we

have denoising and so um you can see there is a
fair amount of uh grain and color noise um in all

of the dim parts here of this image especially
noticeable in the sky background denoise should

help with that and so you have different option
here you can go anywhere from uh 0 to one i think

the default is 0.5 I'm maybe just going to go up
a little bit from the default and go up to like

0.6 okay that took quite a
long time but it did finish and

um now I can see what the non-denoised this
one versus the denoised looks like and it did

make a fairly big difference but I don't know
how well it's going to come across on YouTube

because you're seeing a video that already
has been compressed but let me zoom in even

further and this is a good idea to zoom in like
this anyways just to see okay is the denoising

taking away any detail in the galaxy so let's
go back to just deconvolved and then denoised

and I think it did a really nice job um very
impressive you can see the before there's like

a lot of like color noise and color model and
grain in the background and then just take take

a look at the galaxy too and then here's after
the denoise and I think it's smoothed out a lot

of that grain without taking away really much
detail that we've uh achieved in the galaxy

and we can also we're also going to sharpen up
the galaxy some more later on so I think that

is a good tradeoff and I'm going to keep it like
that and then we'll just go right on to saving and

for saving we want to save as a 32bit FITS file
because we're going to go back into serial and

that is the correct option so click save selected
and then it will ask where do you want to save it

will probably default back to where you opened
up the file which is this working directory so

uh I'm going to go ahead and save it there
and open back up Siril and open our one that

we were just working on from GraXpert so it'll
be called GraXpert Denoised FITS okay and I'm

going to turn back on the auto stretch and don't
be alarmed when you turn on the auto stretch in

serial that all of a sudden it looks much noisier
again because serial's default auto stretch may be

different than the view you the auto stretch you
had up in GraXpert so uh don't worry about that

not an issue at all next thing that I sometimes
do when I have I'm working with Canon cameras

is if I see any horizontal banding artifacts from
Canon cameras I'll uh see if the banding reduction

filter in serial helps with that so I'm not really
seeing enough banding in this to really make this

uh worth it but I just want to show you that um
uh you can play around with this and basically

see like apply did that make it better or worse if
it made it worse just undo and then try again with

different values here for the highlight protection
and the amount and so you can just keep going

back and forth until the banding reduction maybe
helps your image rather than hurts it if you see

any horizontal bands uh in this very stretched
view that's common with Canon and some other

uh sensors again I with modern Canon cameras like
the T7 it's really not too noticeable and I so I

really probably didn't need to do that but I just
wanted to show it just in case okay the next thing

I want to do is run the image plate solver again
so I know we've already gone over this but when

we brought our image into GraXpert and saved there
it's it didn't retain that information so I'm just

going to run this again by typing in M101 click
find type in 300 here 3.72 for the pixel size

and click okay okay and again it came up with
the same solution which is good and we needed

to do that because the next thing we're going to
do is either photometric or spectrophotometric

color calibration um the difference between these
is spectrophotometric also takes into account the

your camera sensor like the uh the noise and the
filters and things in your actual camera there's

a bunch of options here for when you're working
with a spiral galaxy like M101 you can leave the

white point reference as average spiral galaxy um
if you're working with another type of galaxy you

might want to pick that if you're just unsure
of what to choose for the white point reference

usually a G2V star is always a good choice okay
the next thing here is we have to put in our type

of camera so you can see right now it's set to
mono here we're working with one shot color so

we'll switch this to the other side and now you
can see it says one shot color and then it has

a bunch of different sensors here including the
sea stars um it only has a limited range of Canon

cameras so I'll just pick the newest Rebel which
is the 600D that's probably going to be close

enough to the 2000D that I'm not worried about the
differences uh same thing with the low pass filter

it only has one Canon low pass filter in here the
350D but Canon's low pass filters are generally

very similar between models so I'm just going to
leave that uh in there okay okay and then I wasn't

using any additional filter with my Canon camera
if you were you could put it in here all the rest

of this stuff you can probably leave alone it's
going to consult an online catalog uh called

the Gaia Archive which is from a huge survey of
stars it's the biggest star survey uh available

and over 30 million stars so it's going to use
that information from our plate solve to know the

uh color temperature of all of these different
stars in the image and then create a white balance

reference based on the star information as well as
our camera information that we put in here okay so

I'm going to click okay and what it's doing right
now is it's downloading information I'll just move

this to the side here so you can see you can see
it's downloading information about uh from the

Gaia uh catalog it pulled down a particular uh
CSV for this particular area of sky and now it's

done and it plotted lots of different um stars
and then it gives you these plots uh which is

a summary of what it did and then there's a
trend line and that's how it figured out the

white balance reference for this image and then
it gives you some information about that the white

balance factors that it applied down here okay I'm
going to go go ahead and click close and just to

show you the difference here was before a lot more
green in the image and then here's after we color

calibrated it and you might think well it took
out color but don't worry about that because we're

going to saturate the image later and there's
plenty of color information in here there's no

worry about that so um even though this is just a
very bright picture where you might think oh well

it turned it white um it didn't really um it's
just that the auto stretch is very aggressive

okay next up now that we've color calibrated I
want to remove the stars from the galaxy so I

can work on them stretch them separately bring
them both into GNU image manipulation program

and continue working on them separately in there
so I'm going to do that with Starnet Star removal

which is under star processing and the defaults
uh that are checked pre-stretch and generate

star mask are exactly what I want sometimes I'll
turn on this one right here but for now we're not

going to do that because I actually don't want
to make just one finished image at this point

i actually want both the starless and the star
mask separate if this execute button isn't blue

for you it means you don't have Starnet installed
and configured correctly in serial i will have an

addendum that covers that for your system uh but
at the end of the video anyways I'm going to click

execute and this runs pretty quickly on Macs
if you uh have that new version and a newer Mac

and it did a good job here you can see it left
um this this this this this and this 1 2 3 4 5

six maybe seven there's like six or seven other
small galaxies around M101 um these big sort of

blemishes are star halos which you may or may not
have depending on the quality of your telescope um

but don't worry about them because when you add
the stars back in they're not a big deal they're

also quite dim um and we're going to actually
make this sky pretty dark so I'm not worried

about that it looks good uh it did a good job
so I'm going to go ahead and stretch this do an

initial stretch on this result here so to do that
I'm first going to make a box over just an empty

area of sky make a selection so I'm just going
to click and drag on an empty area of sky in the

image then I'm going to turn off the autostretch
I'm going to go to linear mode and then I'm

going to open up image processing stretches
generalized hyperbolic stretch transformations

and move this to the side a little bit and I'm
going to sample this uh box right here with the

symmetry point by just hitting this little eye
dropper and that does an averaging of all the

pixel values in that box and then this is uh the
average number if you normalized the pixel values

from 0 to one so if you normalized them we'd be at
0.03 so it's very very dark um then I'm going to

turn up this local stretch intensity that sort of
uh determines the shape of this curve that we're

going to do and then the stretch factor determines
how far you bring that curve up and so what I'm

trying to do right now is just basically bring
this histogram peak which is represents all of

the data all the pixel values up and out away from
this left hand side then I'm going to go ahead and

apply that and then I want to basically bring this
whole peak back down to the left so to do that I'm

going to go up here to type of stretch change it
to linear stretch and move my black point to the

right until this histogram peak is back over to
the left apply that and then repeat go back to

GHS sample the symmetry point one more time bring
the local stretch intensity way over to the right

and now when you do this the galaxy for me is
popping out but I don't want to go all the way

to there because I think that we're going to
start losing detail in the core so I'm going to

do something more like this where you can see that
you can still really see the spiral arms even in

the core of the galaxy so I'm not stretching too
much at this point maybe just a little bit more

and then I'm going to reset
my black point one more

time for this initial stretch I don't like to
stretch too much and the fact that you know

we just have uh that most of the data is way over
here on the left hand side is normal with an image

like this one where most of the image is black
um and we just have this bright galaxy right here

um which is represented probably by just a tiny
bit of data um in terms of this histogram so I'm

not worried about exactly what the histogram
looks like I'm mostly just doing this on what

the image looks like and I want to make sure that
um I'm not blowing out any detail in the galaxy

core when I'm doing this initial stretch I'm also
not concerned at this point that um we don't have

a lot of saturation we're going to add that later
it's a lot of fun but don't worry right now if uh

the photo looks sort of bleached out or something
like that and I'll go ahead and save this and

I'll save it as just starless and you can if you
are moving to the GNU image manipulation program

save it as a Fitz file that's fine sometimes I in
the past I have recommended switching to TIFF at

this point to avoid issues but let's go ahead
and try fits and see how that well that works

and I'll just leave it on 32bit okay now let's go
ahead and open up the stars and stretch those so

that's the star mask result here and for this
I'm just going to use just a normal histogram

transformation sometimes I'll use an arc sign but
it's warning about clipping pixel values so let's

just rescale values that are under zero so yeah
anyway sometimes I'll use an arc sign for this but

um with a lens like the tear I don't want these
stars to be like super colorful anyway so I'm

just going to use a histogram transformation and
just take this middle slider and move it over to

the left two times applying it both times and that
looks good we can always stretch the stars more

once we move to the GNU image manipulation program
and then I'll go ahead and save this as just

stars.fit and save and we can put these in 32bit
too okay that's it in Siril. I'm going to go ahead

and quit out of serial and open up the GNU image
manipulation program I'll go up here to the file

menu and choose open as layers go to my uh folder
which is in other locations volumes x10 pro yes

allow it to see that go into m101 okay and it was
stars.fit and starless.fit so I'm just going to

hold down command on Mac or it would be control on
Windows so I can click and click and select both

of those to open them both as layers and click
open and it's asking replacement for undefined

pixels do I want to turn them black or white i
want to turn them black i don't know why there's

undefined pixels but let's see what happens okay
I think this looks good and let's work on this

starless image first and I like to go to the
view menu and turn off rulers and turn off the

layer boundary which is that yellow dotted line
just because I find them distracting I'm going

to start by making a selection because I want
to start saturating the galaxy but I don't want

to saturate the background because I don't want
to bring out any color noise in the background

so to do that I'm going to choose my select by
color tool up here which is the fourth tool the

one on the far right in the top row of tools and
I'm just going to click in the background and by

doing that it basically selects the background
as you'd imagine and I guess a few hot pixels

but also the galaxies um if yours doesn't look
like this try changing the threshold and then I'm

just going to go ahead and invert this selection
so I'm going to go to select invert so now it's

just selecting the galaxies and a few hot pixels
if I was worried about saturating those hot pixels

um I could go to select toggle quick
mask and paint with a brush whoops

in black over them and then toggle the quick
mask back off and you can see I did an okay

job but didn't get all of them but I don't really
care i I think this is good enough um if it picks

up a few pixels and saturates them it's probably
not that big a deal cuz our background already

looked mostly black now I'm going to with this
selection I'm going to apply something from the

colors menu and it will add it as a layer effect
to the starless layer but with only this selection

active so it will saturate but just the galaxy
and not the background so I'm going to just start

with just a basic saturation adjustment and let's
bring that way up basically to max and hit okay

okay now what's really cool about the new
GNU image manipulation program is if I

uh zoom in with just the plus button and I go
into this little effects menu on the starless

layer there's a little eye icon next to the
saturation adjustment now and I can turn that off

and on and see exactly what it did and you can see
before we have a fairly ghostly unsaturated galaxy

and after we have a nicely um fairly subtle subtly
saturated galaxy um but I can see already that the

colors that it's bringing out the reds the blues
and the yellows are accurate because we did that

color calibration earlier okay um but this first
go at saturation wasn't enough for me i want to

go a little bit further so I'm going to go back
to colors keep my selection active and go to hue

dash saturation and what's cool about this one is
you can bring up of course the master saturation

that's the default but you can also go into the
different colors and bring up yellows and bring up

uh magentas and bring up cyans right and then
it's only affecting the saturation on the cyan

or the yellow or the blue and I often like to do
this with galaxy work just to sort of give it my

final artistic touch of what I think the galaxy
should look like i know that now we're sort of

wrecking our accurate uh color calibration
so if you are very concerned about like this

being like super color accurate don't do this
just use master saturation boost but if you

uh want to just sort of try to like make the image
look as pretty as possible I sometimes like going

in and messing around with the saturation of
the different colors uh independently and um I

should point out uh that another cool thing with
the new GNU image manipulation program in 3.0

O version is you can always uh bring this layer
effect menu back up and double click and you still

can dynamically edit any of this so I'm right now
dynamically editing the saturation of the yellows

in the in this selection but I can go back to the
blues and dynamic dynamically edit those as well

so that's really cool the other thing I love
about this is just like it keeps the selection

active so now I can just keep adding more filters
so we went through a couple in the colors menu we

can also go here to the filters menu i'm going
to do that go down to enhance go to sharpen

uh parentheses unsharp mask and play around
with this a little bit so the radius is the

size of the kernel that it's going to sharpen
so you can see you can really overdo it that's

with a radius of five pixels but if I try
something more like 2.2 pixels I think that

looks pretty good and then this is the amount
of sharpening again you can easily way overdo

this by applying a huge amount but I just want
just a little bit of um sharpening here so I'm

going to apply it at actually the initial was
pretty good 0.5 maybe just a little bit less

0.4 okay and then I'm going to
go ahead and turn that off and

on and see if I liked what it did
i do i mean it maybe doesn't look

uh super great this far zoomed in
but let me back off just a little

bit okay if I back off a little bit I think that

that sharpening does help define the
galaxy a little bit better okay I'm

going to keep the selection active
and work on the stars a little bit

here so let me zoom back

out okay I'm going to put the stars on top

and let's go ahead and turn their blending
mode from normal so you see right here up

at the top of the layers panel it says mode
normal let's change it to screen oo I think

this is already looking pretty good but
I think maybe the galaxy should just be

a little bit brighter so I'm going to
go back here to my starless layer and

with that selection outline still
selected I'm going to add a curves

adjustment and I'm just going to try just
adding a little bit of an S-curve so we'll

just add a little bit more global contrast
to the galaxy itself and maybe make it just

a bit more the star of the show okay so I'm
just going to add a very subtle S-curve there

and now we're finally done with the selection
so I'm going to get go to select none oh wow

so I think this looks excellent i might not
do anything else to it but let me just see

if there's anything else I want to do i re
I mean really the stars I don't I just got

that the stars are just what they are uh right
out of the right out of the serial i didn't do

anything with them and I think they look pretty
good with just that histogram transformation

i don't think they need to be stretched any

further let me just zoom out and
zoom back in and make sure I like it

yeah so I mean if if you if you got to this step
and your stars look sort of weak and like too dim

you could always just click on your stars layer
and go up here to colors and curves and you know

continue stretching your stars if you need to or
you could do a reverse curve and and make them

um smaller and dimmer so uh that's up to you
but um I really like actually how the stars

look right now so I think I am done if you
think that you'll return to this image in

the GNU image manipulation program you
can do file save and save it as an XCF

file but then when you're ready to share it
with the world you can do file export and

uh go down here to select by file type
to see all the different types of files

it's probably the most common uh file type
for sharing is the JPEG so I'm just going

to choose JPEG image click export and it
will give me some JPEG uh options here you

know like quality so quality is how much
compression it will apply so if you want

um the least amount of compression set quality
to 100 but that will make a bigger file so but

let's try it let's set quality to
100 and let's see how big the file

is okay with quality at 100 it's still under
10 megabytes so that's that's fine it'll save

it'll send on any email attachment and uh I think
that's that's a good compromise so let's go ahead

and open this up and see what our final image
looks like okay and that's it so for me what

really makes an image I think is just getting the
technique down uh on the field making sure you're

in focus and dark skies make a huge difference for
galaxy shots like this um it's not so much having

you know the perfect equipment or the perfect
software dark skies just matter so much um for

getting a nice uh picture of a galaxy where
you have nice color um and and nice detail so

hopefully this uh walkthrough of the free software
was was helpful and if you're watching this and

you're into processing your astrophotography the
next question is what do you actually do with your

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and Squarespace the sponsor for today's video

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off okay here we go with installing the software

on Windows so we're going to start by just
downloading the packages so I have the different

websites up here starting with serial this is the
GitHub for GraXpert where you get the new beta

versions so just scroll down here until you see
assets and twirl that open and then download the

Windows package MSI file starnet you're going
to go to download uh scroll past all this Pix

Insight stuff till you get to the section called
command line tool and then download the zip file

for Windows and the GNU image manipulation program
just click on this big uh orange download button

and then down here click on download directly
okay I have my downloads going directly to my

desktop so they'll all show up right here and then
we'll just go ahead and install them it's pretty

straightforward on Windows but I'll show you some
things that we're going to do to configure serial

after we have everything installed so that you
can work with Starnet and GraXpert directly inside

serial okay let's start installing things so I'm
just going to double click on each setup package

okay when you open up GraXpert for the
first time or actually every time since

this is a beta release it'll just give
you a little warning that this is a beta

release you can just say okay um I'm
going to go ahead and load an image

this can be any image doesn't matter
what it is so I just want to show you

something if you go down here to background
extraction you can see the default is AI and

if you go over here to the advanced menu on
the right hand side you can see there's some

different options here for AI models for
background extraction deconvolution and

denoising and I just usually pick the latest
for each of these but the first time you do any

of these things like let's say if I go in here
into deconvolution and click deconvolve image

it will say do you want to install the AI model
should I download it now and you can say yes and

I'm just pointing that out because um you need a
fairly good internet connection these are fairly

uh slow downloads so just so you know that's going
to take some time and so maybe if you want to do

it all ahead of time before you start processing
you can just load in any image and uh get the

AI models this way by first selecting them over
here in the advanced tab and then just clicking

deconvolve denoise whatever and the first thing
it'll do is actually download uh the correct model

that you've picked over here for Starnet come
zipped and you can just rightclick and say extract

all and then just move this folder somewhere
where you're going to keep it permanently so

I just put it in my documents but you can also
put it in your uh programs wherever you want

to keep it is fine okay then finally let's uh
install click a new image manipulation program

here okay last step is we're going to go
back to serial here and we're going to

configure it so that Starnet and GraXpert
work well within serial to do this go over

here to the hamburger menu in the upper
right the three horizontal lines click

on preferences go down to miscellaneous
and click where it says software location

click on this first folder where and then next
to it where it says must point to a valid Starnet

executable and like I said I put my folder in my
documents but wherever you put your Starnet folder

is fine all you have to do is just find that
folder and double click it and then just find the

uh file within there called Starnet++ this
is the actual executable and when you click

open you should say you should see right in this
box right here it says starnet++.exe you don't

need to do anything with this second box okay and
then this one where the GraXpert executable is is

probably the weirdest thing uh for Windows it's a
little it's not in your programs folder um go down

to this PC click on Windows go down to users and
then find like your user account mine is called

nebul for some reason double click it and then
it doesn't show there's a hidden folder in here

called app data so if you just go up here to the
path and do slash AppData like that capital A pp

capital D ata and press enter it will then bring
you into this app data folder go into local okay

then once you're in local you might be thinking
oh I'll go into the graXpert folder but nope go

to programs somewhere here there it is programs
then there's GraXpert and then within here find

the GraXpert icon right there and click on it and
click open and then you should see GraXpert.exe

right there and then click apply okay then go
ahead and open up an image doesn't matter what it

is and just go to the image processing menu go to
star processing starnet star removal and make sure

that this execute button is blue that indicates
that starnet star removal is working then go

back to that image processing menu and go down
to graXpert interface it will tell you this is

about to be deprecated you can just say okay um
but just make sure that you can access this and

for now you can use this graXpert interface uh
but eventually they're going to move GraXpert

into the Python scripts all right and that is
it for Windows installation so I'm here on my

Macintosh computer and I'm going to go ahead and
download the software that we need so there's

two different versions there's the Apple Silicon
version and there's the Intel version if you're

on an Apple computer that is an M chip then you
have Apple Silicon to figure out if you are on

one of those you can click the Apple up here and
click about this Mac and if your chip says Apple

something Apple M something then you're on Apple
Silicon if it says Intel right here then you're

on Intel so anyways I'm going to click on Apple
Silicon it downloads the latest version which

is 1.4.0 beta 2 as of May 2025 and then they
do have some options for uh donations right

here so I encourage you if you enjoy serial to go
ahead and donate to the team so they can continue

putting out these awesome updates let's go ahead
and just download all the software while we're at

it here while we're in the browser so I'll go on
to the next tab this is GraXpert. GraXpert does

have a website but they also have a GitHub and I
would recommend these um newer release candidate

versions on GitHub because they have some cool
stuff like deconvolution which we'll try out so to

download the latest release candidate we go down
here on this release page and right here where it

says assets just twirl that open and then here's
all the different versions for Windows Mac and

Linux so I am on uh Apple silicon which is also uh
the the architecture of the chip is called ARM so

um if you were on Intel you would choose AMD
if you're on Mac uh Apple silicon you'll choose

ARM right here all right so we have that one
now let's go ahead and move on to Starnet and

uh click into the download page and there's a
bunch of different versions here sort of a lot

of information if you are on uh an Intel based Mac
you'd scroll down here to where it says command

line tool and click on that if you are on a Apple
silicon uh ARM based Mac then you'll right here

on the downloads page in this gray box right here
you'll click on the word here where it says see

new experimental CLI distribution for Mac OS and
this is the one you want so go ahead and click

download there and it will be called Starnet
2T Mac OS.zip that downloads okay while that's

downloading let's go ahead and move on to the GNU
image manipulation program uh this one it's pretty

obvious where to download it's this big orange-ish
reddish button right here at the top and then it

should just um automatically know which operating
system you're on so since I'm on Mac right now it

just defaults to that but you can see there's
also Linux and Windows here and then uh it

also detected that I was on Apple Silicon but if
you needed the Intel version you could see it's

right there anyways I'm going to not do it via Bit
Torrent I'm going to do it directly so I'm going

to use this orange button on the right and there
we go so that's downloading as well now I have my

browser set up to download things to my desktop
so they're all right here on my desktop if you

have your browser set to download things to your
downloads folder you would just navigate to your

downloads folder and they'll all be right there
now we're ready to install these and I'll do them

in the order that I downloaded them so I'll start
here with serial at the top so I'll just double

click this DMG file and then this is a standard
way one of the standard ways of installing

applications on the Mac it's just asking you to
drag the serial app to your applications folder so

I'll just go ahead and do that I'll drag and drop
and if you are updating your serial application

you would want to delete it from your applications
folder before doing this and you can delete it

just by right-clicking and say move to trash
or you can drag it to the trash bin down here

okay once you've done that you've then installed
serial so just to make sure that it's actually

working um I can just go to my magnifying
glass up here near the clock and type in

serial and it says serial is an app downloaded
from the internet are you sure you want to open

it i do I'll click open and there we go so I can
see that it is working and we can delete both the

DMG just by dragging it to the trash and eject
this temporary drive that it created by dragging

that to the trash too okay now let's install
GraXpert so I'll double click the DMG and same

thing just drag this to the applications folder
with that done we can drag these both to the

trash and just double check that GraXpert
installed by typing in grax and hit enter

okay and it says this software uh cannot be
checked by Apple blah blah blah okay okay so

what I'm going to do is I'm going to go up here to
the Apple and click on system settings and go down

here to security privacy and security and then
scroll down and you can see right here GraXpert

was blocked from use because it's not from an
identified developer just click open anyway and

then I'll just use my thumbprint reader or you
could use your password and click open and then

once you've done that once GraXpert will open just
fine every time after that okay and you can see

that I'm on the release candidate version because
there's this tab here on the side on the left

called deconvolution and it has object only stars
only strength and so forth okay so we can quit out

of GraXpert now that that's installed next up we
have Starnet i just double clicked the zip file

to unzip it and then we can delete the zip and
the way that this one works is you're going to

want to put this folder somewhere permanently um
so I keep mine in my documents folder you could

also keep it in your applications folder wherever
you want to put it and this holds actually the

uh application now there are a couple things
that we want to do in addition to install it

okay if you look at the README right here it does
have installation instructions um there's just a

couple little things that um you might run into
problems with even following these instructions

so I'm just going to go through it with you but
I'll keep the instructions open so we can sort

of try to follow them so we can click on the
magnifying glass up here type in terminal it

says open terminal and then run chmod plus x
install.sh okay what it left out there is we

need to actually be in the starnet folder so let
me go ahead and put it where I want which is in

the documents folder so I'll just drag it in there
okay so you can see it's now here in my documents

folder so I have to actually go there in terminal
so I'm going to type in cd for change directory

space and then I'm going to drag in this folder
into terminal just like this and press enter and

so you can see now I'm actually in that folder
so when I run this command this change uh chmod

command which changes the permissions of that
file it will actually know what file I'm talking

about okay chmod plus x starnet 2 okay and then
we're going to also do that chmod plus x on the

install.sh file okay and then the README says okay
just run the install.sh so we're going to do dot

slash install.sh give it
our password and I got this

error uh this is a copy error saying user
local lib is not a directory so I'm not

sure what that meant but I knew how to find
directories on my Mac so what I did was I

went to Finder here went to the go menu
went down to go to folder and typed in

/usr/local double clicked and this is what
I found i found that under usr local there

was no lib directory so we can just make one a
directory is the same thing as a folder so we can

just right click and choose new folder give it our
password again and type in lib enter okay so now

there's a lib folder for it to copy some things
into so we can now type in that command again

/install.sh enter and this time it worked
and I know it worked because look at all

of these files that it copied into that folder
okay with Starnet installed now we'll move on

to the last one gnu image manipulation program
just double click the DMG drag the application

icon this uh character is named
Wilbur to your applications folder

and then you can drag both of these to the trash
okay and just to make sure that worked let's try

opening up the GNU image manipulation program
click open when it asks and yes it is working

okay and the last step here is we're going to
configure serial so that it works natively with

Starnet and GraXpert and to do this we go up here
to the preferences menu which is under this little

hamburger menu in the upper right so click on the
little three horizontal lines that's called the

hamburger menu then click on preferences and then
there's a bunch of different preferences here but

the one we're concerned with is miscellaneous
which is the final option on the left and then

go down here to where it says software location
and if you've never done this before these three

options here will be empty mine are filled in
because I've done this before but I'll show

you how to do it so for the first one Starnet
must point to a valid Starnet executable you're

going to click the little folder icon and go
to where you've stored your Starnet folder

for some reason in the latest version of serial
uh this file picker is in Dutch rather than in

English but it's still pretty easy to figure out
so documents is documenting and um then here's my

Starnet folder and then I'll just click on Starnet
2 here and when you click on it you can see this

is an executable I'll click open and then you can
see it says Starnet 2 right there same thing with

this next one down you just want to click on the
weights file it ends in pt click open and then

GraXpert is a bit trickier uh for some reason
you can see right now it says graxpert.app but

that's actually not I don't know why it defaults
to that because what you have to actually do it's

not going to let you if you just pick graxpert.app
and click open i know that looks the exact same

but it doesn't actually work what you have to
do is you click on this folder and then open

up finder in Finder go to your applications and
then right click on GraXpert click show package

contents go into contents then click on MacOS and
then there's the actual executable and so just

um drag this from your finder to this file picker
window here and then it will actually bring that

up in the file picker and then click open here and
then you can see now it says just graxpert right

there that's the executable now after you hit
apply and then open this back up you can see it

switches to graxpert.app i don't know why it does
that but anyways you have to do it the way I just

showed or it doesn't actually work um but now just
to double check it let's go ahead and open up an

image and if we go to star processing
star net star removal you can see the

uh blue execute button or the execute button is
blue so that means it's working and if we go to

graxpert interface you can see this comes
up and the apply button is blue indicating

this is working as well and since this video is
over 20 minutes long you're now seeing the names

of everyone who already supports this channel
on patreon.com/nebulaphotos and I can't thank

everyone you're seeing here enough for their
support because between sponsors and ads and

the support on Patreon especially I'm able to
run Nebula Photos full-time and that has been

such a blast and if you're are able to join over
on Patreon there are a number of perks that I've

split into different tiers that you can check out
but everyone who supports me at $1 a month and up

gets direct messaging support with me a monthly
Zoom call access to the Patreon channels on my

Discord and much more so I would definitely uh
appreciate it if you could take a look if you are

a supporter of this channel it would really mean
the world to me if you could join over on Patreon

well till next time this has been Nico Carver
and I'm wishing everyone watching clear skies!