Problem with editing stacked image

[ithurtssobadly]

I have taken a small number of light images, dark images, flat and bias images. The thing is that after stacking the images it is still so noisy.. It bugs me off about that stacking problem for some reason
I am doing Afocal Astrophotography (deep sky imaging/planetary imaging with a phone)  if that is the problem in this case
The images of Andromeda galaxy non-stacked and stacked are given in the attached respectfully..
But my question is why does still get noisy after adjusting curves to brighten the image? I thought they kind of reduce using dark flat bias frames?
(Why does the dark area around the circle fov get noisy too?)

 

 

Edited November 19, 2023 by ithurtssobadly
image not previewing

[carastro]

You say you have taken a small number.
normally the more you take the less noisy it is.  Darks  help but nothing beats lots of data. 

Edited November 19, 2023 by carastro

[ithurtssobadly]

21 hours ago, carastro said:

You say you have taken a small number.
normally the more you take the less noisy it is.  Darks  help but nothing beats lots of data. 

Last time i have taken 100 of them but no luck (I deleted them because i was too tired that day not being able to get any data)

[Elp]

Why not just crop the centre of the image into a square then continue post processing?

[ithurtssobadly]

22 hours ago, Elp said:

Why not just crop the centre of the image into a square then continue post processing?

andromeda wouldnt fit then because my telescope's lowest magnification is 48x
I probably should have gotten a telescope that comes with an eq mount for its low magnification
like example astromaster 130

But i did hear dobsonians were better

Edited November 21, 2023 by ithurtssobadly

[Elp]

Cropping the image will have no effect on how a target is framed via your optics. You asked why the outer region is noisy, if you crop it out it'll be removed from the image when you post process further so you won't see it anymore.

[ithurtssobadly]

18 hours ago, Elp said:

Cropping the image will have no effect on how a target is framed via your optics. You asked why the outer region is noisy, if you crop it out it'll be removed from the image when you post process further so you won't see it anymore.

makes sense but also why is the image also kind of noisy ?? 
By the way your Location is funny

[Elp]

It's just the nature of cameras and how they convert to digital format, you'd need to keep a camera extremely cold in order to minimise it (hence availability of cooled astro cameras which pale in comparison to space satellite cameras). Noise is generated by heat within the camera and sensor. If you take an image in complete darkness you'll see the noise in the image. Noise is reduced (averaged) by total time taken with an image (many many hours) and still noise will remain. The vast majority of AP images will have a noise reduction process applied to the image to get the smooth results every beginner expects.

[ithurtssobadly]

38 minutes ago, Elp said:

It's just the nature of cameras and how they convert to digital format, you'd need to keep a camera extremely cold in order to minimise it (hence availability of cooled astro cameras which pale in comparison to space satellite cameras). Noise is generated by heat within the camera and sensor. If you take an image in complete darkness you'll see the noise in the image. Noise is reduced (averaged) by total time taken with an image (many many hours) and still noise will remain. The vast majority of AP images will have a noise reduction process applied to the image to get the smooth results every beginner expects.

any way to cool my phone..?

[Elp]

You can get a Black Shark cooler, some people have adapted them onto non cooled astro cameras but they only work due to conduction from the internals of the camera. But that's not your main issue. You're using a tiny sensor, with a tiny lens so your light gathering capability on the sensor is hindered from the off, the phone is compacted so heat builds up quickly on a phone camera sensor too (an external cooler will not remove the heat from the sensor as there's no direct physical link to it from the outside).

What you need to do is take lots of long exposure images without star trailing and stack them via Deep Sky Stacker, Siril or equivalent.

Then you have to post process the image via software, without this you will never get the results you see on the internet, camera raw data doesn't come out any camera like this by default.

[ithurtssobadly]

53 minutes ago, Elp said:

You can get a Black Shark cooler, some people have adapted them onto non cooled astro cameras but they only work due to conduction from the internals of the camera. But that's not your main issue. You're using a tiny sensor, with a tiny lens so your light gathering capability on the sensor is hindered from the off, the phone is compacted so heat builds up quickly on a phone camera sensor too (an external cooler will not remove the heat from the sensor as there's no direct physical link to it from the outside).

What you need to do is take lots of long exposure images without star trailing and stack them via Deep Sky Stacker, Siril or equivalent.

Then you have to post process the image via software, without this you will never get the results you see on the internet, camera raw data doesn't come out any camera like this by default.

Ooh.. thanks! should i use osc preprocessing without dbf script?(in siril)

Edited November 22, 2023 by ithurtssobadly

[Elp]

Try it. I dont use scripts so can't comment.

Siril is quite easy to use in that the stacking process on the RHS operates left to right if you go through each tab one at a time and complete each stage one after the other.

[AstroMuni]

On 22/11/2023 at 17:34, ithurtssobadly said:

Ooh.. thanks! should i use osc preprocessing without dbf script?(in siril)

I think the siril scripts primarily cater to deep sky stacking. You might be able to edit them to make them work for planetary but as Elp says its best done manually. Alternately use Autostakkert or other tools to stack and then use Siril to post process.

[mikeyj1]

I'll Start by saying i've never stacked Afocal DSO images... but i think there's a fundamental problem with the image stacking when you have such a large non- image area...everything surrounding the 'eyepiece area'  Also not sure how you took bias and flats on a camera phone, but maybe all manual settings?

the only Afocal images i ever had any success with were of the moon, a deep sky object is always going to be really difficult.  Dont bother thinking about cooling the phone, thats a red herring in this case, same thought about changing the scope..  if you want to do deep sky astro on a budget, plenty of 'webcam' cameras that will get you started.  If you have a DSLR you can attach that and get MUCH better images... even without cooling.  Siril is great, and the youtube Deep Space Astro is a great resource for learning all things Siril, especially with a DSLR.  

If you do manage to stack and stretch successfully with the camera phone, well done!  i decided that was a dead end road, only useful for capturing what you can see through the eyepiece, even Jupiter is problematic with afocal in my view.

Sorry if that comes across as a bit negative, but my afocal images only got me started on the long road of astro-imaging...got me really excited, and wanting more...good luck 😉

Mike