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2026-10-09 APP 2.0.0-beta48 has been released !

This is mainly a bug fix release for the reported bugs in beta47. In addition it has a significant User Interface performance improvement noticable when you need to process 1000s of images in APP.

2026-10-03 APP 2.0.0-beta47 has been released !

This is a very big release... many code optimizations/rewrites, many parts of APP are much faster and more precise, especially star analysis and registration are much faster ! Big mosaics will go much faster 🙂

And we introduce a new preview filter, which includes the new Adaptive Deep Sky Stretch and a General Levels Stretch, this has been long over due. The old preview filter (the panel on the right side to stretch and preview your data) has not been updated for a couple of years and it is a critical part of any APP session.

Adaptive Deep Sky Stretch or ADSS is a much more intuitive stretch algorithm. It is also color preserving (which is a great new addition in itself ! ) which means that the highlights are no longer bleached, color is maintained from the linear data while stretching. You can simply stretch your data using the sky background level and signal width sliders which work much easier and more intuitive. You no longer need to fiddle with the old complicated sliders with zoom buttons. All the zoom buttons for the sliders are made redundant. And you can enter slider values in the slider value fields yourself. I will make a youtube video in the coming days to explain and fully introduce ADSS. Once the video is ready, it will be highlighted on the forum.

RGB Combine upgrade !. The RGB Combine Tool has been rewritten mostly. The tool is faster and easier to use and most importantly, the Luminance slider to inject a luminance channel or channels into the RGB composite is now working correctly. It no longer bleaches the RGB colors. Combined with the new ADSS preview, you will get much better and easier great composites with great color! I will also explain this in a new youtube video.

Advice on first efforts

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(@edwallace)
Red Giant
Joined: 6 years ago
Posts: 31
Topic starter  

After wrestling and struggling to image dso's with my ASI 290mm (planetary camera) and tiny fov, I finally got a cooled dso camera, the 1600mm pro. What a difference! I'm attaching my first effort (M81). I know I have a long way to go, but would appreciate some advice. My subs were all properly calibrated with darks only. I have not ventured into flats yet, but I will very soon. I suspect that is part of the problem with this image. The setup is Celestron Nexstar 8se, CGEM II mount, ASI 1600mm, 6.3 focal reducer, EFW and EAF.  ASI 120mm guide camera.

What has caused the milky halo here? Regardless, I am thrilled with the results for my first try with my new camera. I also got a bunch of good data on M101 last night, which I have not processed yet. This image is 15 60sec subs each in LRGB, and 10 5min subs in Ha.

M81 3.22.21 full jpeg

 



   
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(@wvreeven)
Quasar
Joined: 8 years ago
Posts: 2134
 

@edwallace Ed, does the halo also show up on the lights when you stretch them a lot? Or perhaps in the darks and/or master dark? I occasionally still use an ASI1600MM as well and have been using it in the part two years and have not seen such a prominent halo.



   
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(@rickwayne)
Neutron Star
Joined: 7 years ago
Posts: 79
 

Yeah, that would be really, really weird vignetting.



   
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(@edwallace)
Red Giant
Joined: 6 years ago
Posts: 31
Topic starter  

@wvreeven Attaching one L frame with 2 different amounts of stretching.

 

Screen Shot 2021 03 23 at 12.03.15 AM

 

 

Screen Shot 2021 03 23 at 12.01.38 AM

 



   
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(@wvreeven)
Quasar
Joined: 8 years ago
Posts: 2134
 

@edwallace OK this clearly shows that the ring is present in the lights. You'll need flats to correct for that.



   
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(@edwallace)
Red Giant
Joined: 6 years ago
Posts: 31
Topic starter  

@wvreeven That confirms my suspicions. We've just begun a run of many cloudy nights here, so I will take flats soon. Thank you for the info. 



   
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(@edwallace)
Red Giant
Joined: 6 years ago
Posts: 31
Topic starter  

@wvreeven I spent most of today, off and on, working on this. I took flats and darkflats to calibrate them. In the end, the artifact is still in the image, but it is greatly reduced. This was my first attempt at using flats. I suspect I need better flats - maybe a better light source (I used a white screen on a tv). Still, it is progress.

M81 3.22.21 2 jpeg

 


This post was modified 6 years ago by Ed Wallace

   
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(@Anonymous 174)
Joined: 9 years ago
Posts: 5702
 

Not sure if that would be the issue, but a TV might put out a different spectrum from what you want in a flat (broadband), people sometimes also have issues using a tablet for instance. The ring seems optical though, but may be worth trying a different light source like a sky flat or an actual flat-box.



   
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