22 replies to this topic

[lionheartHC]

Hello all. So I finally had my first night of trying to get my entire rig running properly. After four nights of trial and error, I’m to a point where I’m taking pictures. I wanted to use the night to not go overboard but just take a simple lrgb image to figure out stacking and what not. I did not take calibration frames as I did not intend for this to be a great image, more of a trial run. The individual subs looked great. The only issue I had was stacking the blue channel in DSS because it was saying only one sub was applicable. I bypassed this by increasing the exposure setting (I think it fell out of focus). After stacking everything separately in DSS I went to photoshop and when I merged the images, I’m getting nothing close to what the actual color should be. What would be the reasoning for this? Attached is one sub to see the clarity I was getting with all images and the colorful one is the “completed” image.

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[lionheartHC]

I should add, I’m not even sure if the luminescence data is included in this as there was just a section for rgb. When I tried to create another channel and put them lum, it just ruined the photo entirely even though it was the cleanest data.

[pyrasanth]

Please tell the forum more about the camera you are using- is this a one shot colour camera (OSC) or are you using a mono camera with filters?

 

If your using an OSC camera then clearly you have colour but without knowing how and with what the subs were captured with we will be unable to help so please start with these fundamentals- the exact model of the camera!

[lionheartHC]

My apologies. The camera is in the title, I’m using an asi2600mm pro mono camera with filters.

[bsturges]

Looks like you are having a great start acquiring good data to begin with. I can't resist the urge to recommend considering Astro Pixel Processor. I'm sure you've already spent a lot on equipment, but APP has been very good for me over the last several years to get great results without burning out on struggling with software. I've never been a big fan of using Photoshop for astronomy since that is not what it's made for.

[pyrasanth]

Sorry I missed reading the title.

 

Please can you provide a link for me to download a sample of  linear but calibrated and registered LRGB frames- 3 of each will do. I will build an image from this data  then I will be able to tell you what might be going wrong because the colours you are seeing is a bit weird- you should see much closer to the image shown below allbeit that colour calibration has not happened- ignore the technical to the left of the histogram but after an LRGB combination your channbels should look closer to the right histogram.

 

 

Edited by pyrasanth, 26 April 2024 - 01:04 PM.

[Tapio]

Not sure what has happened but seems there's only green and red channels and they are not aligned. And even the scaling is wrong.
I too recommend APP for processing.

[klangwolke]

I’ve got to second getting APP. Try the free trial. It differs from PI in that it is a series of guided steps with reasonable defaults. You can try others like Siril or PI later, but APP is great way to start and not be disappointed or initially frustrated with complex choices at each step.

As for the colorful PS result, make sure you are either doing a create from three grayscale single channels images or if you’re doing layers make sure they are set to add

[lionheartHC]

Update: I got APP and applied all data and it stacked and looks great but theres no color?

[lionheartHC]

Maybe.. just maybe.. I changed from bin1 to bin2 for one of the four filters because I had no idea what I was doing… would that be causing this issue?

[imtl]

What is the total integration time you took. How did you stretch the image? Can you post what you are seeing? Please don't post a screenshot of your screen...

[lionheartHC]

What is the total integration time you took. How did you stretch the image? Can you post what you are seeing? Please don't post a screenshot of your screen...

It was six hours integrated, I'm not sure how to upload anything else as the files need to be very small to upload. I stretched the data with curves in Photoshop.

[klangwolke]

It is likely something which we can help you with but it is difficult to do it without looking at the source files. Like the previous poster stated, if you could put just one of each channels raw files online somewhere and post the link we can help.

[jpengstrom]

Update: I got APP and applied all data and it stacked and looks great but theres no color?

 

 I stretched the data with curves in Photoshop.

Just as a test what happens if you apply a Hue/Saturation Adjustment Layer in Photoshop and pull the saturation all the way up?  Do you get any color?  It’s not unusual to have only a little color, maybe not even detectable, on M51 after it’s been stacked. There are various stretches that will help bring out color. See if AstroPixelProcessor has an arcsin stretch (I’ve never used APP so I don’t know what stretching algorithms it has). 

Edited by jpengstrom, 26 April 2024 - 11:02 PM.

[lionheartHC]

Well, I gave it another go tonight on M101 thinking I could figure out the problem. Unfortunately I ran into the same exact issue. I've provided a link in which I uploaded three LRGB .fit files that were 300 seconds each. If anyone would lend me their time to try and help figure out what's going on I would appreciate it more than you could ever know. I stacked ten total of each on my own with zero color.

 

This link say's it will expire in six days. Signing off at 3:30AM after a long, stressful night. Thank you all in advance.

 

https://filebin.net/g7jxkt4fd0pmmpxc

[Tapio]

Here's what I got using APP and some Photoshop.

Good data so I'm sure it will be better with more data.

 

 

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[jdupton]

lionheartHC,

 

Well, I gave it another go tonight on M101 thinking I could figure out the problem. Unfortunately I ran into the same exact issue. I've provided a link in which I uploaded three LRGB .fit files that were 300 seconds each. If anyone would lend me their time to try and help figure out what's going on I would appreciate it more than you could ever know. I stacked ten total of each on my own with zero color.

 

This link say's it will expire in six days. Signing off at 3:30AM after a long, stressful night. Thank you all in advance.

   I agree with Tapio. The data is not bad at all. There are some pretty tough gradients in the data and I think that is where you are having issues. Darks, Flats, and Bias would help a lot. I had a tough time taming the sky gradients and vignetting.

 

   My processing is not great but I got a result similar to (but not nearly as pretty as) what Tapio posted. (I only used one each of the frames provided just to investigate.) I think the wild colors are due to the gradients and vignetting in the Light frames. This looks to me more like a processing issue and not an equipment issue.

 

 

John

 

EDIT PS:
After thinking about it a while, I should have added a note about the gradients.

When you are processing an image to remove any gradients, be very sure to crop all of the colored edges away where the frames for R, G, and B didn't overlap. Any colored fringes around the outside of an image can really confuse gradient removal software and result in something similar to your first post of M51 in this thread.

Edited by jdupton, 29 April 2024 - 09:09 AM.

[lionheartHC]

Wow… thank you… so it has to be something I’m doing wrong in APP.

[lionheartHC]

Here's what I got using APP and some Photoshop.

Good data so I'm sure it will be better with more data.

When stacking in APP, I choose all light files categorized by RGB, add my calibration frames and "apply to all". After it stacks, I'm left with a detailed mono image that has no color. I've done astrophotography in the past so I know how hard it is to pull out color and details sometimes so I truly know it's not that. Is there something I need to do with the image after its done stacking? Or should it be showing some type of color as soon as it shows you the stacked image? Sorry to bug you, I just wanted to figure out where I'm going wrong.

[Tapio]

When stacking in APP, I choose all light files categorized by RGB, add my calibration frames and "apply to all". After it stacks, I'm left with a detailed mono image that has no color. I've done astrophotography in the past so I know how hard it is to pull out color and details sometimes so I truly know it's not that. Is there something I need to do with the image after its done stacking? Or should it be showing some type of color as soon as it shows you the stacked image? Sorry to bug you, I just wanted to figure out where I'm going wrong.

After you've done stacking individual LRGB files you are left with 4 monochrome images.

To make a color image you then have to use APP combine RGB in Tools tab (in fact before that it's good to use remove light pollution tool in same Tools tab).

Afther combine color you can do calibrate star colors and star reducer.

 

There are excellent Youtube tutorials how to do all of this.

[lionheartHC]

After you've done stacking individual LRGB files you are left with 4 monochrome images.
To make a color image you then have to use APP combine RGB in Tools tab (in fact before that it's good to use remove light pollution tool in same Tools tab).
Afther combine color you can do calibrate star colors and star reducer.

There are excellent Youtube tutorials how to do all of this.

You're the best! Thank you so so much for your time and help. I'm going to reprocess the data this afternoon.

[Oort Cloud]

I'd wager a guess that the individual masters need to be registered to one another so they line up when you composite them into a color image.

[Tapio]

I'd wager a guess that the individual masters need to be registered to one another so they line up when you composite them into a color image.

Yes if individual color channels are stacked separately. But if they are stacked in one go they are already registered.