All language subtitles for [English (auto-generated)] Deep Space Astrophotography with a Star Tracker _ Start to Finish, For Beginners [DownSub.com]

hello world i'm sarah matthews and in

this video i'm going to walk you through

how i image the heart and soul nebulae

from start to finish using a tripod a

star tracker a camera and a camera lens

i'm then going to walk you through how

to process that data to get to a final

color image my hope is that with this

video is going to provide a

straightforward way to image these deep

space objects with a wide field view

using a very portable and beginner

friendly setup just like the one we're

going to use

so without further ado let's go set up

all right so the first thing that we

need to do is determine where we're

going to set up our equipment and be

imaging for the night and there are a

few things that we need to consider

the first is can i see polaris or the

south celestial pole if i'm in the

southern hemisphere because i'm going to

be polar aligning my star tracker to be

able to account for the apparent motion

of the night sky

one way to do that during the day is to

use your compass app and see where north

is or south is if you're in the southern

hemisphere um and that will give you

kind of a rough estimation of where

you're at or if it's at night time and

you know where polaris is you can always

use the big dipper to do that i will

show you here now

[Music]

so in addition to being able to see

players you probably also want to see

your targets um i know that the heart

and soul nebulae are in the

constellation of cassiopeia which is

going to come

through

that

that way

from east to west but if you don't know

where your targets are going to come

through you can always use a planetarium

app like stellarium or sky safari to map

the trajectory of your targets

throughout night of imaging you just

want to make sure that you set up at a

location that is as free

from trees and houses and other

things that could hinder your field as

field of view as possible

for as long as possible and then of

course you also want to make sure that

you find a location that has a fairly

flat surface to set up on this is going

to help a lot with polar alignment just

going to make the whole process a lot

easier

um and of course but certainly not least

uh last last but not

last but not certainly least so tongue

twister sure that you're setting up in a

location that is safe both for yourself

and your equipment um there are a lot of

sketchy places out there and you just

want to make sure you're safe or else

again what's the point of imaging

uh so the next thing that we're gonna do

is go and set up our gear

so the first piece of equipment that we

are going to set up is our tripod i am

using a

faisal carbon fiber tripod um i got it

from amazon i will post a link to it

down below

um so yeah i'll set that up now and just

push down on it

it's

good so now that i have my tripod set up

um i'm going to add the star tracker and

all the components

to the top of it um so let's go do that

now

the star trek that i'm using today is

the skywatcher star adventurer it is the

pro pack and it comes with all these

pieces of equipment

so this is the first piece of equipment

we are going to mount to the top of the

tripod it is the equatorial wedge and it

looks like this

the bottom here will screw onto the top

of the 3 8 inch screw of the tripod

the next thing i'm going to do is take

this adapter here from the equatorial

wedge and i'm going to thread it through

the bottom of my star tracker

so i'm just going to screw this into the

middle here and make sure the little

stopper here is facing forward

now we are ready to mount the star

tracker to the equatorial wedge

so before i add my camera my declination

bracket my counterweight kit and my lens

i like to just do a rough puller

alignment and to do that um i need to

first find my location's latitude i can

find that in a few different ways i like

to use the sky adventure console app

it's free to download so in the app i

just go to the polar clock utility then

i tap on location in the right hand

corner and it shows my location's

latitude which is roughly 39 degrees

now i can adjust my base here to 39

degrees

so now our star tracker is at the same

angle as polaris is in the sky for our

current location

now that i have my latitude in i have

also oriented my setup to be facing

north uh since i am in the northern

hemisphere i'm going to be focusing my

polar alignment on polaris so the front

of my setup is facing north and it

should look like this if you don't know

where north is again you can use your

compass app

now that i have my setup facing north i

need to find polaris and to do this

again you can use a planetarium app like

stellarium or sky safari or you can use

the big dipper as i mentioned earlier by

finding the ladles as two outer stars

then extending the line to the next

brightest star which should be polaris

so once i have players in view i'm going

to want to make sure that polaris is

centered down the top of my star tracker

and i may need to move my tripod legs

until it's center

this is going to set us up for our

accurate puller alignment later

and then what i'm going to want to do

once i have polaris

in my

view from the top of my star tracker is

i want to push down on my tripod the

entire setup and make sure it's firm in

the ground and level so that the polar

alignment is going to be a lot easier

for us after this

now that we have a rough puller

alignment i'm going to start adding the

rest of the equipment to the setup this

is a declination bracket i'm going to

slide it in through right here but

before i do that i'm going to add the

counterweight kit to it so the

counterweight kit comes with this

counterweight pull and this counter

weight right here

and now i'm just going to take the

counterweight pull and screw it into the

bottom of the declination bracket and i

will then add the counterweight to it

and voila now we are going to thread the

declination bracket through the center

of the star tracker

and now i'm going to mount my camera to

the top of the declination bracket this

is a canon eos raw it has a modified

sensor that makes it more sensitive to

hydrogen alpha

just as a note i am going to be screwing

this into the collar of the camera do

not do this if you are using a heavier

lens you would want to make sure that

you are

using a collar

for your lens and screwing that into the

top of the declination bracket to

distribute the weight at the pivot point

evenly

next we are going to mount the camera

lens to the camera this is my rokinon

135 millimeter prime focus telephoto

lens it works great for wide field deep

space astrophotography so in order to

mount the camera lens to the camera i

have a canon mount adapter ef 2 eos r

mount adapter on my camera and it looks

like this

and i'm just going to mount the camera

lens to the mount adapter here now

now i must balance my star tracker to

ensure that there isn't stress to the

gears so first i'll unlock the ra clutch

and move the load parallel to the ground

like this

and it appears that my counterweight

side is heavier and that's a quick fix i

just need to adjust my counterweight and

move it up towards the center of my

counterweight bar like this

[Music]

now that we have all of our equipment on

our setup and are balanced in the right

ascension axis we are going to do a

precise polar alignment and the reason i

waited to do a precise puller alignment

until now is because the polar alignment

could have easily been thrown off during

the mounting of all the other equipment

and when we're balancing

so before we jump into polar lining just

be sure to have these items checked off

number one

be sure to remove the polar scope caps

located on the back and in the front of

the star tracker if you haven't already

it might be a little tricky with the one

in the front if you didn't remove it

before adding the declination bracket

sorry about that

number two add the polar scope

illuminator and its extender to the

declination bracket over the polar scope

this will be used to help with polar

aligning

just be sure to turn it on to the amount

of illumination that you would like

but then once you're done using it be

sure to turn it off so you don't waste

its battery that's me talking from

experience

and last be sure that the latitude base

or the equatorial mount is mounted

securely to the tripod and also make

sure that the tripod itself is level and

sturdy on the ground so that it won't

move

so polar alignment in more depth is

essentially pointing the axis of the

star adventurer to the north celestial

pole which is where in the northern

hemisphere that the earth rotates on its

axis

if you are in the southern hemisphere

then you are going to be polar aligning

your star tracker's axis to the south

celestial pole which you guessed it is

where in the southern hemisphere that

the earth rotates on its axis

so since i am in the northern hemisphere

i'll be focusing my polar alignment

process to the star polaris but if you

are in the southern hemisphere then you

will be aligning your mount to the star

sigma octantus which is the closest star

to the south celestial pole so similar

to sigma octantus in the southern

hemisphere polaris is currently the

closest star to the north celestial pole

in the northern hemisphere but it's not

perfectly situated at the north

celestial pole it actually orbits

closely around the north celestial pole

that being said the reticle inside of my

star tracker which looks like this has

this large circle around the north

celestial pole in the middle and that

large circle is the apparent orbit of

polaris as it rotates around the north

celestial pole so what we need to do is

we need to place polaris on the correct

position on the circle in the reticle

for the current time and my location i

can find out where to place polaris on

the reticle by using the star adventure

console apps polar clock utility

function since i'm using the star

adventure and the reticle you see here

in the app is the same reticle you see

inside the starter adventurer

however if you are using a different

star tracker like the ioptron

skygardener pro for example your reticle

will look different um so what you can

do is you can use an app like polarscope

align instead it is free to download

so once i have the app downloaded and

opened i would want to make sure that

the reticle on the screen and the app

matches the reticle for the star trekker

that i have i think by default it's

usually the ioptron one in the app but i

might be wrong but for me in this case

uh again yeah i am using the

skywatcherstar adventure so i would want

to switch to that reticle in the app

i'll just show you how to change the

reticle in the app just in case you want

to see that so i would go to settings

down here and then under current reticle

i see at the top it's listed for the

ioptron

so what i would want to do is i would

want to change my reticle by going here

and selecting the skywatcher star

adventurer reticle and now my reticle in

the app should be correct and now it is

and that's awesome and it shows where

polaris is on the reticle for my current

location and time

you can manually add in your time in

location or you can just sync it up with

your phone's time and location

so now what i'm going to do is i'm going

to make adjustments on my latitude base

to get polaris in the correct location

on the reticle by looking into the

reticle from the back of my star tracker

i'm going to be using the altitude

adjustment knob here in the front to

move polaris up or down in the reticle

and then i'm going to use these azimuth

knobs in unison together on the back of

my base to move players right and left

so once i have players as close as

humanly possible to the location that i

can see in the app i'm going to tighten

my azimuth knobs and i'm going to be

very careful not to adjust the placement

of polaris while i do this it's often

helpful to tighten the azimuth knobs as

i am moving the

knobs to get polaris in view now we

should be color lined

[Music]

so you might be wondering why my

background's changed and that's because

trying to film the rest of these

segments outside as the day turned into

night as most days do

um turned out to be pretty underwhelming

because i was using a really small

little mobile light to film in the dark

so it was quite unfruitful so i'm going

to film the rest of these outside

segments inside my office but the

concepts i'm going to go over should all

still be applicable as if we were

outside

so now that we have accurate polar

alignment or now that i have

hypothetically accurate polar alignment

we are ready to locate our dsos and

point our setup at our dsos so in order

to find our dsos we can use a

planetarium app like stellarium or sky

savari and we can just plug in the name

of our targets into our planetarium app

and it will show us where in the night

sky our targets are for our location and

the date and time

um or if you're just a pro at this don't

worry about it but i do know what the

heart and soul nebulae are in the

constellation of cassiopeia cassiopeia

looks like a w located between polaris

and the andromeda galaxy uh so all i

would do is look up to the night sky and

find polaris because god knows i've been

staring at it for much longer than i

would care to admit by this point

so i see polaris and then i would just

go down a little bit and i see the

lovely w i know that within the w the

heart and soul nebular app and so now we

are ready to point our setup at our dsos

a few words of caution before we proceed

though do not nudge or bump or throw

your setup like literally at all because

we just polar aligned and you will throw

off your polar alignment and my guess is

you probably don't want to repoll your

line because it's not the funnest

activity to do although it is really

good practice so um be very very careful

is my point

so in order to point our setup at a dso

we are going to move our two axes our

ascension axis and our declination axis

so the first thing i would do is i would

unlock my right ascension axis being

very careful again not to move my setup

so let's just pretend for a moment that

you are the heart and soul nebulae

because you're my heart and soul that's

not weird i promise so what i'm going to

want to do is i'm going to move my right

ascension axis

this way

like this

and then i'm going to lock it so it

stays in place

next i'm going to move the declination

axis here and point my camera lens at

you the heart and soul nebulae

so

because we have a declination axis and

we have a right ascension axis we are

able to point our setup at any point in

the night sky that's just because it's

mathematically proven that way

so now that we are pointed at our dsos

what i'm going to want to do next is

turn on my star tracker to begin

tracking the night sky i'm going to want

to be on the sidereal setting the stereo

setting is identified on the skywatcher

star adventure as this little star here

and now your star trekker will track the

night sky

[Music]

it's probably no surprise that in

astrophotography we are trying to image

these very faint targets in low light

conditions and in order to collect as

much light as we can we have to keep our

camera open for a lot longer during

exposure than we would otherwise

and it also requires us to make our

camera sensor a whole heck of a lot more

sensitive to that light both of those

things create a lot more noise in images

and in order to counteract that noise we

have to take multiple exposures of the

same target and stack it all together to

create a final image that hopefully has

less noise and more light or sometimes

referred to as signal

so in order to be able to actually do

this we have to make some adjustments to

our settings in our camera these

settings that i'm going to go over are

just good benchmark settings for any

dslr or mirrorless camera that's going

to allow us to use a camera lens like

this to be able to use an external

intervalometer to be able to control our

night of imaging and just to have good

overall settings after this we will get

into our actual exposure settings for

imaging the heart and soul nebulae

the first camera setting that we want to

adjust is our white balance generally in

astrophotography you can use daylight or

auto

and then also you're going to want to

make sure that in your camera mode

settings you are shooting in raw and

that your camera files as well are being

taken and stored as raws too

next be sure to turn off the long

exposure noise reduction setting in your

camera you don't need to worry about

noise reduction because we'll take that

out in post

and then your camera focus be sure that

it is set to manual focus we are using a

telephoto lens um and we are going to be

manually focusing it same if you are

using a telescope

and then last your camera mode since we

are using an external intervalometer and

we'll be taking multiple exposures we

want to make sure that our camera mode

is set to bulb

[Music]

next we are going to focus our camera

lens again i'm using a rokinon 135

millimeter prime focus telephoto lens

and it looks like this

the first thing that i want to do is

turn my camera on and open up the live

feed on the back of the camera

now i'm going to change the iso to 1600

anything above 1600 is going to be good

for this

then i'm going to change the aperture on

my camera's lens to about f 2.8 anything

below f4

is good because you're going to be

letting a lot of light in

and then i'm going to change my camera

lenses focus ring to the infinity sign

and then i'm just going to begin

focusing so the key to focusing stars is

to move your camera lenses focus ring

from left to right and watch the stars

get bigger and smaller once you start to

see them get smaller keep going on that

direction on your focus ring

and then once you have pinpoint stars

just don't move your focus ring at all

[Music]

next we are going to dial in our

camera's exposure settings for imaging

the heart and soul nebulae and for those

who don't know what exposure settings

are with regard to dslrs or mirrorless

cameras basically just pertains to the

shutter speed the aperture and the iso

so i'm just going to go over those at a

very high level and how they interact

with one another so that we can

better determine what the best settings

are going to be for our imaging session

here

let's start with shutter speed shutter

speed basically means how long is each

image going to be in my imaging session

how do i determine how long each image

should be well i'm so glad that you

asked because it depends on a few

different things the first is how bright

is my dso the second is how light

polluted are my skies am i using a light

pollution filter because if i am i can

usually have longer exposed images the

third is how good is my polar alignment

if i have superb polar limit well then i

can usually have longer exposed images

but if i have bad polar alignment i'm

going to get star trails a lot earlier

on and the fourth is

[Music]

now let's talk about aperture now

aperture pertains to your camera's lens

and how much light it's allowing to get

to your camera sensor the wider the

opening the more light that's getting to

your sensor the smaller the opening the

less light that is getting to your

sensor

[Music]

[Music]

now iso pertains to how sensitive your

camera sensor is to that light

so putting it all together once i have

my camera pointed at my target and i

have focused my camera lens and i have

adjusted my camera settings i like to

determine my camera's exposure settings

by first taking 30 second exposures with

my camera lenses f-stop or the size of

its aperture kick down about one or two

stops from its widest aperture which in

this case the widest aperture is f 2.0

so i'm going to decrease the aperture to

its next f stop which is f 2.8 and the

reason i like to do this is because i

want to keep my stars from bloating as

the temperature changes throughout my

night of imaging and i also want to help

with any potential star drifting that

might happen so for iso i like to start

anywhere between 800 to 1600 iso and in

this case i started with 1600 iso so the

key is to kind of just find out what

works best for your specific target with

your exposure time settings and your iso

settings um for example i didn't have

very long with this target i had about

two hours to collect light so i knew

that i needed to collect a lot of light

pretty quickly so

what i went ahead with is a 1600 iso

with 90 second exposures at f 2.8

but when in doubt though just look at

the histogram of your test images and

assess from there you want to try to

have your images as histogram mountains

of data in the 50 range or slightly to

the right on the histogram that way no

data from shadows or from highlights are

being clipped

[Music]

now that we have adjusted our camera

settings and determine what our exposure

settings should be given the brightness

of our dso the darkness of the sky the

accuracy of our polar alignment the wind

conditions and how long we have to image

the target we can set up our external

intervalometer up for success

since we are going to be taking multiple

long exposures that are over 30 seconds

apiece remember we are taking 90 second

exposures i'm going to need an external

intervalometer like this to control my

imaging session because i do have a

canon my camera does not have an

internal intervalometer but i believe

nikons do the intervalometer i'll be

using today is by shoot it looks like

this but i will link an intervalometer i

recommend down below if you're

interested so first let's dial in the

settings the first section is for delay

which basically means how much time do

you want before the first image starts

so say for example that you need some

time to walk back to another area like

your tent or go back inside your house

you'll want to set up some time for

yourself in your delay for you to walk

away from your imaging setup so that you

don't cause your first or your first few

images to be blurry from walking around

nearby so i'm going to input 10 seconds

here so from right to left the first

section is for seconds the second

section is for minutes and the third is

for hours and so 10 seconds should look

like this

next we have long and long refers to you

guessed it how long do you want your

exposures to be so remember i want mine

to be 90 seconds and in this case i

would input it as one minute and 30

seconds so i'll input a 1 in the minute

section and 30 seconds in the second

section

next we have interval or here it's

listed as intvl which essentially means

how much time after each sub-exposure is

complete do you want before the next sub

exposure starts i like to use anywhere

between one to five seconds for dsos but

it's totally up to you and really just

depends on how quickly your specific

camera can write and store a raw file

also just remember that the longer the

interval the more time your camera

sensor has to cool down a bit these

cameras like a dslr or a mirrorless

camera are not cooled so i'm going to

input three seconds

next is the letter n which stands for

the number of exposures you want to take

since i only had about an hour and a

half to two hours of visibility with the

heart and soul nebulae and i would be

taking 90 second exposures i input 75

frames

now you are ready to plug it into your

camera here on the canon eos raw it's on

the side here

and also make sure that your

intervalometer isn't just dangling i did

put some velcro on the back of the

intervalometer as well as on one of the

legs of my tripod i can attach it that

way just be sure that the cord is out of

the way of the tracking

and also just double check that your

tracker is actually on and on the serial

setting

and you are ready to press start

[Music]

yay we have made it to our calibration

frame section of this video

uh before you skip over this section

just hear me out calibration frames

really do make your final images so much

better um i will go over them now for

you if you're interested and if you're

not just pass over it but yeah

calibration frames are your friends they

are awesome

so here we go

so as i mentioned before calibration

frames really do make our images of the

night sky so much better because they

help to remove all the unwanted parts of

our images like artifacts from camera

bias noise heat noise dust and so many

other things but ultimately what they're

doing is helping to increase the signal

or the light to noise ratio in our final

image so that your final image is a lot

cleaner and has way more detail in it so

what i'm going to do is i'm just going

to go over the types of calibration

frames that there are for dslr and

mirrorless cameras i'm just going to

keep this at a very high level and then

i'm going to go over how to take them

i'm not going to get into any of the

math here because getting into the math

is

could be truly its own series in and of

itself so let's jump into the types of

calibration frames

so first yes we took our light frames

and light frames were the images that we

took for our subject but bias frames are

calibration frames that help to reduce

the fixed pattern noise in our images

so your camera will have readout noise

from reading each pixel on your sensor

as you take each image and this is

called bias and it is random so in order

to eliminate that you can isolate the

bias by taking bias frames that will

then be removed or calibrated from the

light frames

now dark frames help to counteract the

noise in astral images that happens as a

result of the temperature of your camera

sensor during each exposure

your camera sensor warms up quite a lot

while each image is being taken which

causes thermal camera noise and thermal

camera noise manifests itself in images

as grain and unwanted artifacts that

ultimately reduce the quality of your

images so you're going to need to take

and use dark frames to counteract that

noise in your astral images what this is

going to do is it's going to improve the

signal to noise ratio and improve the

details in your astro images

flat frames are essentially a portrait

of your optical system and this includes

the dust that shows up in your optical

system

that show up in your images as little

dust shadows or dust motes

as well as the vignetting or the

darkening of the corners of your images

so by taking flat frames we can actually

eliminate the dust shadows and

vignetting

how do you take calibration frames so

with bias frames bias frames are going

to be taken with the lens cap on your

camera lens in complete darkness you're

going to want to set your exposure time

to the fastest shutter speed on your

camera for me with my camera it's 1 8

000 of a second so just be sure to take

your camera out of bulb mode and switch

to manual mode to do this

so with iso be sure that you keep it at

the same iso that you took your light

frames with which for me was iso 1600

you'll also want to do your best to take

your bias frames at the same temperature

as your light frames so just try to take

them immediately after you take your

light frames

last but not least take anywhere between

20 to 50 bias frames

like bias frames you're going to take

your dark frames with the lens cap on in

total darkness but the exposure length

is actually going to be the same

exposure length that you took your light

frames with so in my case i took 90

second or

a minute and 30 second exposures for my

light frames so i'm going to take the

same amount of exposure length for my

dark frames also be sure to set your

camera mode back to bulb for this

iso wise we are going to be using the

same iso that we did with our bias

frames and our light frames which for me

was 1600 iso and just like with your

bias frames be sure to take these dark

frames at the same temperature that you

took your light frames at so try to do

them immediately after you take your

bias frames or your light frames

the next thing you'll do is set your

intervalometer to take anywhere between

20 to 25 of them

unlike bias and dark frames which were

taken in a non-illuminated environment

flat frames are actually going to be

taken in the presence of light this can

be either natural light such as at dusk

or dawn or with an electronically

illuminated light such as a tablet with

a white screen

i like to diffuse the light by carefully

wrapping a white t-shirt on the front of

my lens and then using an ipad with a

white screen in front of the camera just

be very very very careful not to adjust

the focus ring at all when you do this

and also be sure to take these before

you disassemble your camera and your

camera lens doing so afterwards would

render your flats useless because the

optical train has already been tampered

with

for your camera settings though switch

your camera mode from bulb to aperture

priority or av this will allow your

camera to determine the optimal shutter

speed for your image

and then for your iso just keep your iso

the same iso that you took your light

frames at again i took mine at 1600 iso

so my flat frames will also be taken at

1600 iso

and then you're going to want to take

about 30 frames

now we are done with our calibration

frames and our light frames and we can

bring them over to our computer and

start to edit them

[Music]

i have gone ahead and transferred my

images onto my computer from my camera's

memory card

i have organized them into their

respective folders so i have my biases

here my darks here my flats here and my

lights

what i'm going to want to do is start to

review my lights for any weird anomalies

like out-of-focus stars or star trailing

or

satellite trails or plane trails so i

would just click on my lights folder and

i would start with my first one

so just as i know i've already gone

through my images um so i could just

click on the spacebar with the mac and

here's my first image

so again what i was looking for is any

out of focus stars so any stars that

were bloating if i had any star trail

any of my images as well as any trails

from satellites or from planes so yes i

do have a blue hue in my images and

that's because i used a light pollution

filter

but i can fix that in post

but yeah i ended up with about 60 total

light frames out of the 75 that i took

and now what we can do is bring them all

into cyril and begin processing them

with our calibration in light frames

reviewed and organized into their

respective subfolders

in a folder on my desktop we are ready

to go ahead and calibrate a line and

stack the images to get to a

stacked image and then we'll take that

stack image and we will process it a

little bit more to get to a final color

image

so jumping back into calibration frames

really quick here

what we're going to be doing is using

them to remove artifacts in our light

frames and then what we will do is

use those calibrated light frames and

align them

and then we will integrate them or stack

them all together to get to that final

stacked image i was talking about

this final stacked image is going to

have increased signal to noise ratio

which again this basically just means

more details or light and less artifacts

so to do this it is fairly simple we are

going to be using a pre-processing

script from a software called cyril and

we will also be using the software to

process our final image a little bit

more

so for those who don't know about serial

already surreal is a really great free

astronomical imaging processing tool

that is compatible with mac windows and

linux operating systems

so here i'm on the surreal.org website

you can download

the application to whichever operating

system that you have so i have a mac so

i would download the 64-bit mac os

and then i would just follow the

installation

instructions after that it is very very

straightforward to download and install

but once you have it installed open it

up and it should look like this i'm

running version 1.0.4

so the first thing i'm going to bring

your attention to is this blue scripts

button here at the top of the interface

so in this drop down menu you're going

to see a whole host of different

pre-processing scripts so i'm only going

to be using one i'm going to be using

this one shot color pre-processing

script or osc because a i used a

mirrorless camera but if you use the

dslr camera or some other type of

one-shot color camera this is

another option that you would want to

choose from

and also again because i have all of my

calibration frames my biases my darks

and my flats and my light frames and

i've organized them like i showed you in

those respective folders

i'm going to be using that script but if

you don't have all those calibration

frames say for instance you only took i

don't know darks and lights well then

you can install more scripts like i have

so here i am on free astro.org under the

scripts page all you need to do is just

google um free surreal scripts and it

should be the first website listed

so this page has the instructions for

the serial scripts and then i would just

scroll down

and here you'll find all those other

scripts i was talking about of course

you can create your own scripts in

serial but

these are already created which is

really handy

so again yeah say for instance you only

have your dark calibration frames and

your lights well that's no problem we

can actually download and install

this this script into surreal so it

would be that one shot color

preprocessing without flat dot ssf file

so i would just click on it and then i

would download it and then in my

downloads folder i would move that file

into the surreal application folder

there should be a folder for scripts and

i would just move it under there

then i would um want to close

surreal and then open it back up and

then it should be listed here down in

the scripts

so again yeah i have all my calibration

frames and my light frames and i did use

a one-shot color camera my mirrorless

camera so i'm going to be using this

one-shot color pre-processing script to

get to a final stacked image but the

next thing that i would need to do is i

would need to tell serial what my home

directory is for the scripts to be or

for that script to actually work

so i would come over here to this blue

little house here and i'm going to click

on that

and i already have my home directory

selected

so

it is in a folder so my home directory

is a folder that's on my desktop um so i

have again

my biases organized here my darks here

my flats here and my lights here you

again want to make sure that they are

organized just like this with this

script for the script to work

so i would press open and you should see

the home directory listed here

so the next thing that i'm going to do

is actually run the script so i'd come

down to osc

pre-processing and this is basically

just a warning that you know doing all

these steps on their own

may yield better results but that's fine

i'm just going to run the script anyways

and then what you'll see here over in

the console app is the application or

you'll see the script running

this will probably take a few minutes

or hours depending on

what your computer's processing power is

if it ends up failing it could be for a

couple of reasons one is because you

aren't using the correct script or you

didn't organize your files correctly or

it could be that you don't have enough

working memory on your computer so

um

you know those could be two options that

you could try troubleshooting

so once it's done i will come back

all right and we are done here so it

looks like here on the console section

that it took a total of six minutes and

three seconds to run the process

so now i'm going to want to open up the

image so i'm just going to come up here

to open and you should see two new items

in your home directory folder i have

process folder or i have a process

folder here and i have my final stacked

image which is result.fit so open that

up and it looks like this doesn't look

like much because it's still in a linear

state and so i will apply a non-linear

stretch

and a little bit but in the interim i

will apply a temporary autostretch

coming down here and switching that to

auto stretch

so over here um you're gonna see so up

here you're gonna see your final image

under rgb

you're gonna see the blue channel in

your final image the green channel of

your final image and the red channel in

your final image the rgb channel or

combination channel is just going to be

um for visualization anyways so you

can't use any processes on it so i'm

going to be working on the red channel

just because i can see more detail with

it but whatever

channel is the most

detail friendly for you pick that one to

work in

so the first thing that i'm going to

want to do is crop any weird black edges

that i have i did have

a few and you just want to remove those

because they will throw off some of the

other processes we're going to be doing

so i'm going to do crop

like this all you need to do is

click left on your mouse and then draw a

box

like this and then

press right on your mouse and it's going

to give you all these different options

i'm going to press selection because i

want to keep my crop ratio to three by

two

so that looks pretty good for now um i

may adjust it later actually that later

has come so i'm gonna just do it to here

feel free again to do whatever crop that

you want just make sure that you are

getting rid of any black edges on the

edge of your

image so right click again

crop

and there we go

so here i'm just going to go back to

linear

auto stretch i'm actually going to go to

histogram histogram is another

type of auto auto stretch it's just more

intense

so here is my image again with the crop

next we are going to remove gradients

because there are a whole host of them

from light pollution

um so gradients from our images like

light pollution either from the moon or

nearby cities

will show up like this they're just

unwanted light signal and gradient like

this becomes more apparent after

stacking when the addition of the pixels

brings out the signal from the noise

oh and also the gradient isn't always

evenly distributed across the images we

stack together so removing the gradients

becomes a little bit more complex once

we've stacked it into a final image so

in order to get rid of these complex

gradients we're going to use a tool

called

background extraction

so i'm going to come up here to image

processing down here to background

extraction and the dialog box looks like

this

so for the interpolation method i'm

going to keep it at rbf for the

smoothing factor i'm going to keep it at

0.5

and then i am going to generate the

samples you can

add the samples manually if that's what

you prefer to do but i just found that

with this data set

generating it automatically helped the

most because i did have a lot of

gradients and i used the light pollution

filter and i didn't uh white balance it

before

so

anyways yeah you may want to just mess

around with these settings and see what

works best for you guys so i'm going to

click on generate and you'll see some of

these red boxes show up on your nebulae

and if that's the case

just right click on your mouse over the

red boxes that are on your nebulae and

remove them so i'm going to do that now

the reason i'm doing this is because i

don't want the synthetic model that this

is going to create to have any of the

model based off of my nebulae

so i am pretty happy with that

so i'm going to come down here to

correction type it's going to be

subtraction

sometimes i might do division but i'm

just going to keep subtraction for now

and i'm gonna click on compute

background

[Music]

all right so

my image is looking decent um

yeah again this has been a tricky image

for me to process because yeah using a

light pollution filter that i didn't

didn't create a

custom white balance for is a little bit

difficult here but that's fine

all right so now that we have done

background extraction i am going to use

what's called photometric color

calibration so i'm going to be color

calibrating my image

so i'm going to come up here again to

image processing color calibration and

photometric color calibration and

basically what this does is it

pulls data from different catalogs

online astronomical catalogs and it will

match the colors for your specific

region of the night sky which is really

cool so

i have two targets here so i'm just

going to pick one i'm going to do the

the soul nebulae so the catalog uh

designation for that is ic 1848. i'm

going to click on find

[Music]

and there it is in two different

catalogs so i'll just keep the net one

selected and then

for your focal distance and pixel size

if it doesn't automatically populate go

ahead and click on get metadata from

image and then if it doesn't populate

from there

just input it yourself

so it should be your focal distance of

your lens or your telescope and your

pixel size of your camera

and then keep everything else the same

and click ok

[Music]

you'll see down here in the console

window that it is running

and it's been applied so we can close

out that process now the next thing that

i'm going to want to do is i'm going to

just sharpen some of the details and

reduce some of the star size here

so i'm going to come up here to image

processing down here to deconvolution

so um i'm going to

um

just reduce the radius of the kernel

size to about 0.8 the key with

deconvolution is to make sure that your

stars do not have what's called

d-ringing or have ringing around the

star which would show up as

like a black halo because you've reduced

the star size so much that there's just

an absence of the actual

pixels

um from before so

yeah i don't see that right now um but

yeah just make sure that you're looking

out for that and then coming down here i

would probably change the iterations

down or up to about 24. again these are

just example parameters for my data set

mess around with

these parameters for your data set

and then i'm going to click apply

[Music]

okay cool

oh another thing that i forgot to

mention about color calibration the

photometric color calibration is that it

um helps to white balance my image as

well so the next thing i'm going to do

is soften this image a little bit and

i'm going to try to bring out the

details of the nebulae a little bit more

so i'm going to come up here to image

processing and i'm going to come down

here to median filter

and i'm gonna keep the kernel size uh

three by three but the iterations i'm

going to increase to five

but for modulation i'm going to decrease

to

let me just write this in 0.5 um so for

your data set just see what works best

for

for it these are again just examples but

i found that these parameters work

pretty well so maybe start there and

then press apply

and

boom it is done so um what i didn't go

over before is uh here are the before

and after um little arrows so here's the

before the median

filter and here's the after so it did a

really good job

so now what i'm going to do is i'm going

to stretch the image i'm going to move

it back to a linear state so yes it

looks like this and there are a few ways

that i could stretch the image

but i'm just going to keep it really

simple because my goal with this whole

video has just been to keep it as simple

as possible both from the equipment how

to use all of it

all the way to

processing i just want to keep it as

simple as possible

so i have changed it back to a linear

state of a view and then i'm going to

come over to image processing down to

histogram transformation and here is the

histogram um transformation dialog box

so i'm going to apply the auto stretch

to the

image here in its linear state the one

that we were um using a little bit

before this so i'm just going to click

here

and so what it's done is it's applied

that auto stretch

um so i'm just going to

maybe bring down the black point a

little bit

to that that looks fairly decent

okay

so the next thing that i'm going to want

to do is remove some of this green haze

over my image

yours may have even more green haze and

that's because of your bare matrix in

your dslr

there are more green pixels so you would

see a

um you would see more green in your

image so that's fine all you need to do

is come up here to image processing

uh remove green noise and

we are going to apply you can just keep

everything as is

so press apply

and it's done a fairly good job

so the next thing that i would want to

do is i would want to increase the

saturation a bit so i'm come up here to

image processing

color saturation

and i'm going to keep the hue at global

so it means all hues

i'm just going to increase the amount

probably to

i don't know actually let's just see

what looks

good okay that looks

fairly decent

move the background factor

just keep it at one

press apply

okay so

oh actually i don't like that

so let me redo that again

so let me just bring it up to

i don't know 0.5 does that look okay

okay that looks pretty good so yes i do

have a little bit of gradient still left

over um

that's just been an issue i'm gonna try

using background extraction one more

time

so let me just press generate

and

i'm gonna compute background

see if it does anything

okay actually that looks pretty good

i am fairly happy with that so i'm gonna

go with that

and um i could just keep this as my

final image um or i could bring it into

photoshop or but

again the whole like point of this video

was to get you to a final color image um

fairly quickly because i know that

sometimes it you know astrophotography

can be kind of a very long process so my

hope is is that you know here is a final

working state image and you know we've

brought you from the beginning of how to

get that data all the way to this point

so um you know i'm not perfectly happy

with this image but

i am happy with it in the sense that it

is pretty good for um you know

what we were working with so yeah feel

free to bring it into photoshop or

or something else if you'd like to um

make it a little bit more punchy but

yeah um i really appreciate if you've

made it to the end of this video

and if you have any questions please

feel free to um ask them down below and

as always i really appreciate all of

your ongoing support and um you know if

you like this video please consider

giving it a like and subscribing to my

channel

and until my next video i hope you all

have clear skies

[Music]

you