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2023-09-16: APP 2.0.0-beta23 has been released !

Improved performance again, CMD-A now works in macOS File Chooser, big improvement for bad column cosmetic correction, solved several bugs

We are very close now to  releasing APP 2.0.0 stable with a complete printable manual...

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Whats the difference in integration vs RGB combine.....

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Neutron Star
Joined: 6 years ago
Posts: 82
Topic starter  


a couple of questions i have regarding integration vs RGB combine tool.

1. What is the reason to combine images with different filters (IR-cut and dual band Ha/OIII) in the RGB tool and not directly via the integration tab? Since I have some annoying stack artefacts when using the RGB combine tool with data not shot at the same night and with a different camera angle/rotation (i don't have a measure on my telescope to see the degrees of rotation of the camera so the framing is not always the same).

2. With the RGB presets, why would i have to load my extracted data (Ha & OIII from a dual band filter on a OSC camera) as R, G & B and just as Ha or OIII. And how does this work when using RGB data and i want to add Ha & OIII from my OSC camera, can I use the Ha and OIII feature then for the applicable channel, or do i need to use R for R // B for B // G for G // R for HA // G&B for OIII? 


Just some things i don't know the details of and my help me with integrating and getting the 'correct' colors.



Universe Admin
Joined: 6 years ago
Posts: 5701

1. With RGB Combine, you can vary the amount of data to be added to the RGB composite. The framing and such shouldn't be a problem I think, APP should be able to register the frames like they are, are you seeing some issue in this regard?

2. Not completely sure what your question is, but with an OSC camera and that filter, you can directly extract Ha and OIII from the raw data by choosing the algorithm in tab 0. So that will result in having a mono frame with the resolution intact (very nice feature only APP has) and you can integrate it into a Ha or OIII stack. Then you can take your RGB frames, seperate the R, G and B channels (split channels option) and stack those as mono as well. In RGB combine you can then add each integration to your liking to the R,G and B channels for a RGB composite.

Neutron Star
Joined: 6 years ago
Posts: 82
Topic starter  


1. But the RGB combine doesn’t have MBB which creates stack artefacts when the data isn’t exactly aligned if combining multiple sessions.... So if i just use integrate (6) for my dual band and osc rgb data it would only create different colors? Or would i be losing data as well? 

2. Yes i understood that part, but why load Ha as red and not as Hydrogen Alpha in the rgb tool?

thanks Vincent! 

Neutron Star
Joined: 5 years ago
Posts: 138

I adapted this method to my lights with L-Pro and L-eNhance filters: on OSC Asi533.

Extracting Ha & OIII files and combing with R, G, B files (also from LPS filter as Optolong L_Pro) using an OSC and Optolong L-eNhance filter. 

RGB Integration
1. Stack and integrate the color files or other filter (LPro) as you normally would but do no post processing on it yet.
2. Clear the input files out of APP (or close and restart it) and load in the stacked integrated color file as a light file.
3. Click on the Calibrate tab (tab 2) and scroll to near the bottom and check the "Split Channels" and click on Save Calibrated Frames. This will then split your composite color image into 3 RGB images that have all been preprocessed. These are the three files you will combing with the NB files

Ha and OIII Integration
4. Now for the narrowband images. Clear everything out of APP and on Tab 0 (Raw/Fits), leave AAD (Adaptive Airy Disc).
5. For the algorithm, select Ha-OIII extract Ha. 
6. Click on Load (tab 2) and enter your lights, etc. for your L-eNhance frames and appropriate calibration frames.
7. Click on Register (tab 4) and select Use Dynamic Distortion Correction.
8. Click on Integrate (tab 6) (automatic).
9. Once the integration is complete for the Ha file, go to tab 0 and select the Ha-OIII extract OIII algorithm. Click integrate in tab 6 and this will integrate your OIII data.
10. When the OIII is complete you now have 5 files: R, G, B, Ha, and OIII. Now the files must be registered and normalized together so that you can combine them.

R, G, B, Ha, OIII Registration/Normalization
11. Restart APP and in the Load tab (tab 1) load in the R, G, B, Ha, and OIII files. 
12. Click on Analyze stars (tab 3) and click on the Analyze Stars button.
13. When Analyze stars is complete, Click on Register (tab 4) and then click on Start Registration.
14. When registration is complete, click on Normalize (tab 5), select Advanced mode and then click on Normalize lights. When complete, click on Save Normalized Frames.

Combining R, G, B, Ha and OIII
15. Click on Tools (tab 9) and select Combine RGB.
16. Add each file, one at a time. R for Red, G for Green, B for Blue, Ha for Red, OIII for Green and OIII again for Blue. Or choose a predefined algorithm.
17. Go ahead and click on Calculate and get a starting image. 
18. Tune the top slider for each frame as desired. I usually start with something like Ha slider 2.0, OIII Green 1.0, OIII Blue 1.5, Red 2.5, Green 1.0, Blue 1.5 and then go from there. Keep in mind, you do not want to overpower your image with Ha and OIII or you will destroy your natural star color.
19 When you have finished tweaking your color, click create and then cancel. This takes you out of the Combine tool.

Final Tweaks
20. Select the combined fits file you just saved. Now you are ready for your initial crop, light pollution reduction, Star Color Calibration and HSL Color. Then you can adjust your saturation, contrast and sharpening.
21. Do any final cropping and/or rotating and save your Tiffs and JPEGs as desired.

These are a couple of final results..following above method

Alan Tan reacted