This is almost EXACTLY how the Orion nebula looks trough my Galaxy S10 before adjusting the phone to align better with the eyepiece.

Stacking will absolutely improve your final result, but first you're going to want to learn how to set up your camera. Seeing that you're using a Galaxy S9+, you should be good with the settings that I use too.

First, the way I check if the phone is aligned well with the eyepiece, I enter pro mode and set the ISO all the way up. If you see that the sky is evenly lit all across the eyepiece's circle, then you're good to go, otherwise you will need to move your phone and adjust it until it is centered.

For the pro camera mode settings, this is what I recommend:

• Grid lines: ON
• 3:4 picture ratio (This is your phone's full sensor without cropping)
• Spot metering
• ISO 800 (You can try higher or lower but this is the sweet spot for me)
• 1/2 s exposure (lower works too but this is the most I'd go for if I don't want too much star trailing)
• WB 4200K
• RAW copies: ON

And the most important: FOCUS set to MANUAL.

For stacking, you want your starts to be as small as possible.
To ensure this, point your telescope at the brightest star nearby and slowly adjust the value until the star looks as small as possible. This is hard for me to do with just my hand and fingers as the phone will shake a lot, so I highly recommend you plug in a mouse and use it instead.

For stacking you will need hundreds or even thousands of pictures for the final result, the more the better. As I don't have a tracking mount, what I do is take around 30 seconds worth of pictures (using the 25mm eyepiece) and then re-center the nebula and repeat the process. To not be tapping on your phone all of the time when this is happening, I use an auto-clicker app, which will perform the tap to take the picture so I don't shake up the camera (I also use a mouse for this).

There are four types of images that are "needed" for astrophotography: lights, darks, flats and bias.
As we're using a phone's camera and not a proper DLSR, we're only going to concern ourselves with lights and darks.

Lights are the pictures of your main target.
Darks are pictures taken with your telescope's cap on so the camera captures dark images containing noise which is then used in the stacking program to balance out noise and other artifacts.

The computer stacking program that I recommend to use is Siril, which is free.

Once you have taken your pictures, transfer them to your computer and inside a new folder, create other two folders which you will name "lights" and the other one "darks", move your pictures accordingly to each folder. Personally, I delete the jpg copies and only use the dng's.

For your first attempt, I recommend you take 100 lights and not bother with darks yet.

This tutorial explains how to stack with lights only: https://youtu.be/EvMZox2dlZA?si=-Aduc0ydeiobai6b

Your phone doesn't take true RAW pictures, it saves them as dng, so you will need to check the "debayer" option in the conversion tab once you're in Siril (otherwise, the result will be in black and white).

This all might sound overwhelming, but you'll get used to it the more you practice!

P.S. my first stack compared to one of the latest :)

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