okay this is part 2c
of my series on lagoon nebula without a
star tracker
uh in this part we're going to look at
pixinsight which is a paid
program available on linux, windows and
mac i'm going to be using it on my mac
i realize there is a newer version that
includes
starnet but i haven't updated it i
haven't updated
that version yet because it doesn't work
with the mac operating system that i'm
using which is an older version of mac
os
so just a personal thing but if you do
if you are on like the latest mac
operating system
i would recommend uh updating to the
latest pix insight version where starnet
is included and they've made some
improvements too but if you're like me
and you're on an older version of pix
insight you can always just
google star net plus plus and
download it from the sourceforge site
and follow the instructions
to get it working on your operating
system
um it's right here under pix insight
module
um i did that i'm on mac os 10.13
and i have starnet working just fine
within pix insight here
under the processes so that's an option
too
okay anyways enough about setting this
up um
we're going to be processing some files
of the lagoon
nebula this was done without a star
tracker just on a tripod
and i'm going to be use using a script
to do the processing specifically the
batch pre-processing script
i have tried weighted batch
pre-processing which is sort of like the
newer update of batch pre-processing for
me
it doesn't work so well because i i
usually have lots of
problem files and so uh i don't
i haven't figured out a way to weight
those appropriately i need to do batch
preprocessing
with calibrate only on and then look
through my files in something like
subframe selector or blink
before moving on to registration and
integration
so this might work for some people but
i'm still on
batch pre-processing
i always the first thing i do is turn on
this calibrate only
i typically don't register or stack
using this
because i don't know what my files look
like yet and so
i like to look through them and make
sure i'm stacking the best ones
okay it's pretty simple to use you just
add your lights flats
bias dark frames into these tabs here
just using the buttons down here at the
bottom
so i'll go ahead and do that everything
is on my desktop here in this folder
called lagoon
and if you want to follow along you can
download these files
from my website the link will be in the
description
but basically i'm just selecting my
files and adding them
using the appropriate buttons here so
i'll just go ahead and speed this part
up
since it's a little boring
okay so i've added everything now
i'm just going to leave most things on
their default parameters
for the most part the defaults in batch
pre-processing script are just fine
these are cfa images meaning that they
have a color filter array
um specifically a bayer array in front
of the sensor
we're not using any master bias master
dark master flat
but if you did have a master bias or
something like that you would just
only add the master bias here and then
just click this little check box
next to use master bias in order to use
that
we're not going to be doing any
registration so i don't have to add a
registration reference image but i do
have to specify an
output directory so i'm just going to
make a new folder
called bpp
save to that and then we can go ahead
and click
run and uh
it will do its thing it takes it'll take
a while because we're doing hundreds of
frames so it has to create all those
master
calibration files and then calibrate all
of our
lights using those so we'll get a little
time here
and then when it's all done we'll we'll
move on to the next step
okay the batch pre-processing script uh
finished and i went ahead and closed out
of it
next up we're gonna go to the process
menu and go down
to all processes
subframe selector and i use this uh
process to determine which frames have
the best focus so finding a good
registration
uh frame and uh it also will tell you if
there's any frames that seem really odd
and uh
you know out of whack so
i'm just going to enter in a few little
parameters here our subframe scale was
around
i think 17 arcseconds per pixel
i don't know our camera again so i'll
just leave it on one
we'll change our camera resolution to 14
bit
and then i'm just going to click up here
where it says sub frames i'm going to
click on the add files button
and in the bpp folder
there's another folder called calibrated
then light
then debayered and so basically
it creates logs it creates masters of
your calibration files and then
this calibrated folder is for where it
actually calibrates your flats and your
lights
we don't want to use these ones because
these are are in black and white
we want to use the debayered ones where
they're in full color
and then i'm just going to click and
shift-click
to select all of these files and click
open
okay and now i have 282 subframes
ready to analyze and so
we're going to go ahead and analyze them
or measure them um
using uh this process and
it does take a while i'm going to go
ahead and start it just by hitting the
little circle down here
and uh you can see it it starts over
here
it does about uh eight subframes at a
time
um if for some reason you have to stop
the process
and then pick it back up it does save it
into memory so
uh just i've i've often had to like
it takes up a lot of your computing
resource and your memory so
if for some reason you have to stop it
and do something else like some other
work
uh it's fine you can always pause it and
then come back later
but it does take a while so i'm going to
go ahead and cut the video here and then
we'll see what it says when it's all
done
measuring all right the subframe
selector finished
analyzing my frames here
i have 282 lights that it analyzed
and the first thing we want to look at
is
this measurements window so bring that
to the front
and don't pay too much attention to the
actual
numbers that i'm going to be showing you
because these are going to be
wildly different based on your
conditions your focal length all kinds
of things
the main thing that we're trying to do
with this is just look for outliers
so obviously there's at least or there
is
two outliers here in my 282 frames in
terms of
full width half maximum which is a good
uh corollary to focus so basically
uh two frames are way way out of focus
and we should uh get rid of those frames
um if i look at eccentricity
it's the same two frames that are way
off so obviously there's something wrong
with those two frames i'm guessing
probably they were are when i moved the
camera
to refo to reframe uh maybe it was still
going or something
or they were just test frames when i was
testing focus
so in any case i want to get rid of
those the other thing that i want to do
with this script
is find the the frame that has the best
focus
um so uh i'm just going to do that by
sorting up here
so if i sort by instead of sorting by
index which is just the number
of frames in order i'm going to sort by
fwhm
full width half maximum and
if i sort ascending
that will give me at the top here the
frame that has the best
focus so i'm just going to write this
down it's image
one zero two eight um there are ways
that we could
sort them and then output them um and
you know eliminate ones we don't want
using these expressions and
the output option i'm not going to show
that right now just because with so many
frames that's going to take too long and
take up
so much space on my hard drive so i'm
not going to use those features
but maybe in another video i can show
how this
expressions window works so i'm just
going to write down
i want to use 1 0 2 8 when i do image
registration because that's the frame
with best focus
okay then i'm going to sort fwhm
full with half maximum descending and
from here i can see that the two frames
that i want to delete
are zero nine zero four and
one thousand
yeah the two frames that i want to
delete are zero nine zero four
this one with a huge full width half
maximum
and uh number one thousand so i'll just
write those two down nine zero four one
thousand
and then i'm going to do is just
go into my
lagoon folder go into the batch
pre-processing folder
calibrated light debayered
and just find 904
and delete it
and then find frame 1000
and delete that
now it doesn't show up here this doesn't
this doesn't update live that i've
gotten rid of those but
um i know that those are the two frames
that were huge outliers that were
there were big problems just to double
check i can sort by eccentricity here
and yep it's the same two ones 904 and
1000. so
getting rid of those um has given me a
nice
fresh start here with all clean data
um and then the only other one that i am
paying attention to here is one zero
two eight that's the frame that i'm
going to use to register against
and just to double check that it's
there's nothing wrong with that frame
i like to open it up and look at it so
you can just do
file open again you're going to go
into that batch pre-processing
calibrated light debayered
and find it in here
one zero two eight and open it up
get this out of the way
i'll just apply it apply an auto stretch
to this
and zoom in a little bit and yeah
this looks good i don't see anything
wrong with this frame so
i'm going to use this to register
all my lights to
so we can go ahead and move on to that
that's all that i'm going to show in sub
frame selector today
maybe again maybe in other videos i can
show more about it because it is a
useful tool
and we're going to go right on to image
registration so if you go to processes
image registration and choose star
alignment
this is a process that will let you
automatically align using a reference
image and match
star patterns so i'm going to choose up
here where it says reference image i'm
going to switch it from
view meaning that would be if we had a
view open we could use that but i
already closed the image so we're going
to choose
file and then i'm just going to pick
that one that i just had open
1028
click open
i'm going to leave all of these settings
alone the only thing that i'm going to
change from the defaults is i'm going to
turn off generate drizzle data that
would take a long time if i left it on
and i'm not going to drizzle this data
because it's not dithered
and then where it says target images
here i'm just going to click add files
and pick
everything left in my debayered folder
since we deleted those two
problem files
okay and then i'm going to create an
output directory meaning just a folder
i'll put it just in my lagoon folder and
i'll call it
reg for registered
okay and that's it um i usually just
leave all these other settings alone
the only time you would need to change
them is if you were having issues
so for instance if you were having
issues with it not being able to find
stars in your image you could turn
up or down the detection scales you
could change the noise scales hot pixel
removal all these different
things sensitivity to try to pick up
more stars
basically if you hover over any of these
they do tell you
a bit about them and how you would use
them
but i think the defaults are going to
work for me so i'm just going to go
ahead and leave all of those alone
and just hit the circle icon down here
to apply
this process globally on all the target
images
and this does take some time
the more cores you have in your
computer's cpu the faster it will go
because it is a very multi-threaded
process um
but uh for my uh
five or six year old laptop here it'll
probably take i don't know an
hour or something so i will just leave
it alone
and come back when it's all done okay it
finished aligning
all of our images using the star
alignment process
if i go over here and hover over process
console
it tells me that all 280 images
succeeded
zero failed zero skipped and it took
about 26 minutes
okay so next uh what we're going to do
is go ahead and close out of that all
the files that we just aligned with star
alignment are in that reg folder
and we'll open up another process called
image integration
so i'm just going to go to the process
menu go down to image integration
and then image integration again
i'm just going to go ahead and click
this little
reset button down here in the lower
right
just to make sure all the settings are
the defaults
then i'm going to click add files
go into lagoon reg
and select all the files in the
registration folder
click open i'll just make sure that i
have 280 here
i do then in the image integration
tab i'm going to open that and the only
thing that
i'm going to
then i'm going to open the image
integration tab i'm not going to change
anything in here but i just want to show
you these are all the settings that we
want to use
average noise evaluation
evaluate noise you know generate
integrated image
all these default settings are what we
want under
pixel rejection 1
we want to change this we don't want the
rejection algorithm set to no rejection
that wouldn't be smart what we want is
to change it to
windsorized sigma clipping and what that
will do
is anything that are outliers anything
that aren't in the central part of the
standard deviation meaning hot pixels
any other kinds of noise will get
thrown out when we do the averaging
so we definitely want to turn on a
rejection algorithm
i would recommend turning on clip high
range in addition to all of these other
clipping options right here okay
with that set i can go ahead and click
the circle button down here to apply
this globally meaning that it's going to
apply it to
all the frames in our input images list
and
there's no place to save them because
what it's going to do is after
it integrates all these images
it will create the image right here in
the window
um and then we can keep working on it so
again
this is going to take a little time so
i'm going to speed up the video
okay that process is finished we have
the integrated file here
and to see what it looks like we can
turn on an
stf auto stretch you can do that in one
of two ways you can either just hit the
little radioactive button up here
or you can open up the process called
screen transfer function which gives you
a few more options
so i'm going to go ahead and open up the
process and
what i want to point out in screen
transfer function is that normally
the channels are linked meaning that
it's going to stretch all three
equally but if you unlink the channels
then it will apply
different stretches to each channel and
you'll get a better color balance
in your preview so i'm going to go ahead
and unlink the channels and then hit
this
radioactive icon to auto stretch it
and that shows me what we have here so
you can see this is a nice wide field
shot of the milky way you can see
there's some color balance issues on
each side where the signal-to-noise
ratio goes down there's also some
registration artifacts down here at the
bottom
so the first thing that i'm going to do
is i'm actually just going to crop
in on this picture so that we don't
deal with these low sig low signal high
noise areas on the sides and at the
bottom
and to do that i'm going to go and open
up the process
called dynamic crop if you go to process
menu and go down to geometry
it's called dynamic crop
and it just works like any other crop
tool you can just
draw out a box here
something like that and then hit the
green check mark to crop the image
okay that's done next thing i'm going to
do
is apply a dynamic background extraction
to this
and so that's also under processes it's
the second option down
background modelization and then dynamic
background extraction
and you first want to click on the image
and then just click into areas
where you should have a fairly neutral
black so i'm mostly just going to
sort of pick areas here where there's
either dark sky like in this corner
and this corner or dark nebulae
um you don't want to click on you know
anything bright or a star
you just want to pick the more neutral
black parts of the image that could be
considered background
and i'm just sort of trying to add them
with some coverage so getting each
corner getting each side
and the middle
and usually about 10 or 12 will do it
you can see that this one down here is
red
and that means that it wouldn't be
included if we tried to run this process
now so what you can do to include that
sample is increase the tolerance so it's
by default it's 0.5 i'm just going to
try to raise it to 1
and then under sample generation click
resize all
and then you can see that sample down
there changed from red to white meaning
it's now
included okay with that done i'm going
to go ahead and open up the target
image correction menu right down here
and choose subtraction and then hit the
green check mark
what it then does is it creates a
background model
uh using the samples that we just gave
it
to create a
model of the background which you can
see right here
looks a little funny if i don't up the
bit depth there we go
so this is the background model and then
we can see what the image looks like
with that background model subtracted
okay good i'm going to go ahead and
close
that process i'm going to close the
background model and i'm just going to
put these pictures
side by side so you can see what it did
so here's the before and here's the
after
and hopefully you can see on your screen
that um
on this one the sides especially look a
bit washed out
and like low contrast and in this one
because that background model was
subtracted it looks a lot better
so i'm just going to minimize this one
and we'll put it over to the side
and we'll keep working on this one at
this point i'm going to go ahead and
save this just so we have something to
fall back to in case there's a program
crash or something like that
i'll just save it to the desktop as an
xisf file which is the
default format in pix insight
okay the next thing i'm going to do is
i'm going to
stretch this but before i stretch it i'm
just going to increase saturation just a
little bit with the curves
transformation
so i'm going to open up curves i'm going
to switch to the saturation mode which
is this s
over here on the right and just pick a
spot about
two-thirds up on the curves line and
just stretch that
up like that and apply it just by
hitting the square right here
okay and hopefully you can see that
increase the saturation a little bit
i'm going to keep this curves
transformation open because i might want
to do it
a couple times more as we're stretching
the image
i'm going to take off the auto stretch
i'm going to open up histogram
transformation which is under intensity
transformations in the process menu
and i'm going to start stretching the
image so i'm going to open
i'm going to say i want this to apply to
integration
underscore dbe that's our background
extracted image right here
and i'm going to take this middle slider
and move it
pretty far over to the left and then hit
the square to apply
you can see even with that much stretch
we're just barely seeing some stars
so i'm going to apply it again
okay this time i'm going to do a little
bit less of a stretch
something like that and hit the square
okay now we can start seeing the image
and
so i'm just going to keep backing off
the stretch just a little bit
and now we have enough breathing room
here that i could
take this shadow slider and just move
that over a little bit to the right
you want to be careful here down here it
tells you how many pixels you'd be
clipping completely to black
and so right now it says i'd be clipping
172 pixels to black i'm comfortable with
that amount but if it said like
20 000 pixels are clipping the black
that would be way too much
and so i would i would want to back off
that a little bit
okay i'm going to apply this actually
before i apply that last stretch let's
go ahead and just add
some more saturation just by applying
this saturation curve
okay cool and then i'm going to apply
the stretch
perfect okay
and honestly uh
you know this is already looking really
nice um
we might not really have to do much else
to it uh you might be happy with just
that amount of processing and picks
insight all we did was
a background extraction a crop and a
and a stretch there are a few things
though that i'm noticing that could be
improved on
so i'm going to close these two
processes one is that we have a little
bit of green noise over on this side of
the picture
so i'm just going to try to run a noise
reduction
sc r green
and i'm going to start it at something
like 0.3
because i don't want to run it at full
strength or it usually takes out
too much green and screws up your color
balance but i'm just going to try to
take out a little bit of that green
noise
okay and i think that did a pretty good
job
here's the before you can see this this
side of the picture especially really
has this green cast to it
and there's after and it looks a lot
more naturalistic
but we could try running it again if you
think that it needs it so you can always
just apply it again
okay and it took out even more green
here's the first you can see it's really
green on this side
here's the first application of sc r
green and here's
the second application and
yeah i think i like two applications so
i'm going to leave it like that
okay um
the next thing we can do is um
remove the the stars
from the image and
boost the milky way a little bit and
then add the stars back
in to do this we use a process
called starnet plus plus if you have the
latest version of pix insight installed
it
comes with pix insight now as a main
process
you can always update to the latest
version to get it
personally i'm on an older version just
because of the age of my mac but
for most people you can just update to
the latest version and get it that way
okay for a wide field image like this
i don't think the stride of 128 is going
to do a very good job so i would usually
lower it to 32 or even 16.
let's try 32 and see how it does so to
apply it
all you do is either just hit this apply
button
or drag the new instance icon onto your
image
and let go
and it does of course like everything in
uh
processing take a while so we'll let it
do its thing
and catch up when it's done here's the
result of the pixel math operation
it took 49 minutes
with a stride of 32. one thing i forgot
to do is make a copy but we can always
do that
now and then i'm just going to undo
the star removal on this one so now we
have a starless image and the image with
stars and let's just
name them appropriately so i'm just
going to type in
stars there and double click on this tab
and call this
starless and i'll go ahead
and save these as well
okay then what i'm going to do is on my
starless image i'm going to apply
some curves so i'm going to go to
process intensity transformations
curves transformation and i'll leave
this saturation
one up like that but i'm also going to
just do the rgbk
and just do a slight s curve like this
and let's go ahead and hit the preview
the real time preview to see what this
looks like
oh and that's the real-time preview of
the star image that's not what we want
so let's click on this one
and then do the real-time preview
and i think that's a little bit too much
on the saturation so i'm just going to
edge off that a little bit and i'm just
going to add a little bit more
shadow definition just by
making this s curve
just a little bit more extreme okay
let's go ahead and apply that
okay so here was the before
a little bit washed out and here's the
after just a lot more
extreme contrast i think the it made the
overall picture just a little bit
too dark but the thing is when we
combine these two the picture is going
to get a lot brighter so that's fine for
now so i'm just going to leave it
like that and
let's go ahead and now combine the two
images back together
and we're going to do that with
pixelmath so
you can open up a pixel math just by
going to
process pixelmath pixelmath
and we can use a single rgbk expression
what we want to do this is a little bit
funky and i'm not going to be able to
explain it exactly what it's doing but
the tilde key which is under the escape
key on your keyboard it looks like a
little
sort of curved dash that's an inversion
of all the pixel values so we want to do
tilde parentheses
tilde stars
times which is the asterisk
tilde starless
end parentheses okay let me
okay and what this is is this is the
equivalent
of a screen blending mode in
photoshop but in pix insights pixelmath
so let's go ahead and see how that looks
okay so i have that typed in
then what i'm going to do is i'm going
to open up the destination tab and
change it from replace target image
because i don't want to do a replacement
to create new image
and i want it in the rgb color space and
then i'm just going to hit
the square to apply okay
and we get this image
and hopefully you can see other than
just being brighter than our original
image
it also made these nebulae pop
out a bit more and a lot of the
dust the dark lanes in the the milky way
as well
to make those dark areas of the milky
way pop even more
there's actually a script in in pixin
site it's under the script
menu up here and it's under utilities
and it's called dark structure enhanced
script
so let's try running that as well in our
new image five
i'll just hit okay
okay so this is the before
that's the after you can just see that
the the dark
dust lanes throughout the milky way got
a little bit enhanced through that
the next thing we want to do though is
reset the black point on this image and
we can do that
again with curves so i'm going to open
up curves transformation again
reset it and open up a real-time preview
and then i'm just going to drag down
here
over in the shadows area okay so
now we can see what um
the starless boost did to the image
hopefully you can see that it's it's
pretty subtle
but um it definitely boosted up the
the nebular regions a little bit
and i think sort of improved just sort
of the drabness of this one
by making it a little bit punchier
we can also zoom in on some feature and
see how it looks
okay so there's our lagoon and trifid
i'm just going to apply that same
view over here to the just stars image
and hopefully you can see in this view
that it just
it minimizes the sort of the
um dominance of the star field a little
bit it makes the nebulae i think pop out
a little bit more and appear just a
little bit punchier
um let's look at another feature here
so here's the star cloud in our new one
and here it is in the old one and so it
still looks like a really beautiful star
cloud but it just
i think it just looks a little bit more
refined over this on this one
and then here's the omega and the eagle
and again i just think they pop out a
bit more um in this one
but basically i'd be i'd be happy with
either image so if for some reason
starnet uh isn't working for you i think
i think this looks just fine but this
just looks a little bit more finished to
me
okay and then for saving
we can always save it as a pix insight
file so i can just call it
lagoon pi final
you can save it off as a tiff file
and that's good if you want to bring it
into another program like gimp or
or photoshop for some final fixes
but we're going to call this done and so
i'm just going to save it as a jpeg
and i'll go ahead and increase the
quality to a hundred
okay and then here's our final result
out of pixinsight this is my final video
in this
lagoon no tracker series so i can now
sort of evaluate the different
pictures we've produced i have to say
without doing any color calibration i
think that the stars
and colors in the pix insight version
are just really good i didn't really
have to do anything with it
and i think it also did a pretty good
job of retaining detail
i didn't try any noise reduction which
i think is is good for this image i
don't think it can really hold up too
much noise reduction i think that was
actually a mistake
when i um did it in photoshop
uh because there's there is
this is the stock dslr if i haven't said
that and there is quite a bit of detail
you can see the cluster
in the core of the lagoon and you can
see um
sort of the lobes of the lagoon and how
it's more
bluish in the middle and and then it is
pink
towards the edges i just think
everything came out really
nicely in this um pixel insight version
so for me pix institute is still really
um the best processing software for
astro images that i have
i understand why some people though
don't want to buy it because it is a bit
expensive but
to me it is it is worth having in my
tool kit
so this has been Nico Carver from
nebulaphotos.com
i hope you enjoyed this video you can
always leave questions and comments
below and until next time, clear skies!
