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Autostakker output is looking bad and I dont know why


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I tried stacking multiple times. Tried selecting images that looked similar. Still got this issue where there is a ring around the moon and you can see that the surface details are gone and there are boxes visible. This was my first attempt. I even tried changing the stack percentage to 50 but no success. In another attempt, the image looks washed out instead of being detailed. I am confused. I had taken the photos at the same time. Please tell me where I went wrong and help a beginner out

Screenshot 2021-05-28 132425.png

DSCN5939_lapl5_ap25900.tif DSCN5939_lapl5_ap25900.tif

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Hi Arby69 and welcome to the forum.

What imaging kit are you using? Could you tell us the scope, camera and mount? I ask as the image I just opened, looked to have a bit of rotation which might happen if you are using an Alt/ Az mount.

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Hi and welcome to SGL.

It looks like you are using video format that has a lot of compression.

Those squares are very indicative of Jpeg type compression at very high settings, so codec used might be Mpeg (which is just "motion" / video type jpeg).

Info on the gear used would be very helpful in explaining this and also - if you could post single frame of those that you are trying to stack - for analysis.

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2 hours ago, Swoop1 said:

Hi Arby69 and welcome to the forum.

What imaging kit are you using? Could you tell us the scope, camera and mount? I ask as the image I just opened, looked to have a bit of rotation which might happen if you are using an Alt/ Az mount.

 

1 hour ago, vlaiv said:

Hi and welcome to SGL.

It looks like you are using video format that has a lot of compression.

Those squares are very indicative of Jpeg type compression at very high settings, so codec used might be Mpeg (which is just "motion" / video type jpeg).

Info on the gear used would be very helpful in explaining this and also - if you could post single frame of those that you are trying to stack - for analysis.

I am using a very beginner kind of setup.  Nikon P900 with amazonbasics tripod. The shots for this were taken without my tripod using the burst shot feature. I have attached an image. I am using the JPEG format since my camera doesnt allow me to export RAW. Any tips on how to approach stacking with such a basic setup would be great help

DSCN5946.JPG

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Arby69,

If you are shooting hand held, you will really struggle to get sharp frames for stacking- exposures below around 1/60th second on small (50mm) lenses or 1/125- 1/250th second on longer lenses tend to show evidence of camera shake which will degrade your stacked images.

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Posted (edited)

I'm not sure what would be the best course of action in this case as I haven't used it like that (it won't produce nice results because of compression).

First thing that you should try is to set alignment point to larger size - maybe try 104 or 200 pixels in size.

One that you are using is too small and will pick up individual compression artifacts and just amplify them (it will not align on lunar features but rather on compression artifacts).

Once you do that, I'm afraid you won't be able to sharpen much as sharpening will again bring out that blockiness in the image - but give it a go anyway and see what you can get (here I mean for example Registax wavelet routine for sharpening).

Another thing is to stack only best 10% of frames (not sure how many frames you have in total).

Since you are using stationary / not tracking mount - there is field rotation. AS!3 is capable of dealing with that, but you need to turn it on.

image.png.b57bc68e3c5a5a0ff9adf7512e161111.png

there is section with field rotation parameters:

image.png.58d5f91a833342fce60ef646fee0def9.png

You need to know your location and time of recording - first / last frame and enable field derotation.

Edited by vlaiv
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1 minute ago, Swoop1 said:

Arby69,

If you are shooting hand held, you will really struggle to get sharp frames for stacking- exposures below around 1/60th second on small (50mm) lenses or 1/125- 1/250th second on longer lenses tend to show evidence of camera shake which will degrade your stacked images.

I avoid using high ISO setting to avoid noise in my images. I can use my tripod to capture the frames. Problem with burst shots is that they significantly degrade my image quality so there is no use of stacking if my original image is like 640x500. So I take individual images one after other. Do you suggest I capture images on high ISO settings? Is there a way to get rid of high ISO noise?

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1 minute ago, Arby69 said:

I avoid using high ISO setting to avoid noise in my images. I can use my tripod to capture the frames. Problem with burst shots is that they significantly degrade my image quality so there is no use of stacking if my original image is like 640x500. So I take individual images one after other. Do you suggest I capture images on high ISO settings? Is there a way to get rid of high ISO noise?

Point of stacking is to reduce noise (or rather improve Signal to Noise Ratio - SNR, sometimes written as S/N).

Actual exposures used for lucky type lunar images are 1/250 - 1/500 range (few milliseconds). Individual frames are very noisy, but once you stack couple hundred of them - SNR improves and you get very smooth image that can be sharpened well.

Another thing that you should not worry about is if your individual shot is a bit darker - you don't need to properly expose it, that is another thing stacking does for you - it creates very high dynamic range and you can brighten image later.

 

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Posted (edited)
11 minutes ago, vlaiv said:

I'm not sure what would be the best course of action in this case as I haven't used it like that (it won't produce nice results because of compression).

First thing that you should try is to set alignment point to larger size - maybe try 104 or 200 pixels in size.

One that you are using is too small and will pick up individual compression artifacts and just amplify them (it will not align on lunar features but rather on compression artifacts).

Once you do that, I'm afraid you won't be able to sharpen much as sharpening will again bring out that blockiness in the image - but give it a go anyway and see what you can get (here I mean for example Registax wavelet routine for sharpening).

Another thing is to stack only best 10% of frames (not sure how many frames you have in total).

Since you are using stationary / not tracking mount - there is field rotation. AS!3 is capable of dealing with that, but you need to turn it on.

image.png.b57bc68e3c5a5a0ff9adf7512e161111.png

there is section with field rotation parameters:

image.png.58d5f91a833342fce60ef646fee0def9.png

You need to know your location and time of recording - first / last frame and enable field derotation.

Well, my camera has no other option but JPEG. I will follow the steps that you have mentioned but if my images look blocky then there is no point of stacking! What do you suggest I do? Also how many frames would be enough? Currently I was working with 300 frames

Edited by Arby69
left out details
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1 minute ago, Arby69 said:

Well, my camera has no other option but JPEG. I will follow the steps that you have mentioned but if my images look blocky then there is no point of stacking! What do you suggest I do?

As first step - try doing what I suggested - use larger alignment point and deal with field rotation.

For next session - check if you can set quality of images in your camera / quality of Jpeg. There is often option to select between file size and quality of image - use highest quality setting to minimize artifacts.

Some cameras have hacks that enable saving of raw images instead of compressed. Canon range of compact cameras (non DSLR type cameras) has something called CHDK that you can use to obtain more control over camera.

https://chdk.fandom.com/wiki/CHDK

Maybe Nikon has something similar?

If not, then alternative will always be to purchase second hand DSLR type camera for this purpose and use it with lens or scope to get raw files.

When I first started doing planetary shots - I used modified web camera - and had issues with compression, however, I was able to get at least some results. Switching to camera with raw output really improved things.

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1 minute ago, vlaiv said:

As first step - try doing what I suggested - use larger alignment point and deal with field rotation.

For next session - check if you can set quality of images in your camera / quality of Jpeg. There is often option to select between file size and quality of image - use highest quality setting to minimize artifacts.

Some cameras have hacks that enable saving of raw images instead of compressed. Canon range of compact cameras (non DSLR type cameras) has something called CHDK that you can use to obtain more control over camera.

https://chdk.fandom.com/wiki/CHDK

Maybe Nikon has something similar?

If not, then alternative will always be to purchase second hand DSLR type camera for this purpose and use it with lens or scope to get raw files.

When I first started doing planetary shots - I used modified web camera - and had issues with compression, however, I was able to get at least some results. Switching to camera with raw output really improved things.

There was a similar hack for nikon but it has been deleted off the internet. Its only for a few cameras now. I have been waiting for a hacked firmware for so long because P900 is a point and shoot but can perform better. I've read that Nikon firmware is very difficult to crack and so far no one has been able to reach even close to the chdk type of firmware for Nikon. 

For the image quality, I have set it to FINE instead of NORMAL that it was by default. Looks like this is the best image I will get. However, I tried stacking 640x480 images that I took while taking burst shots and they stacked surprisingly well. No distortion, no blocks, just a clean image at the end. But ofcourse, that image was of no use because it was so low res to begin with anyway

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