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.
Hello,
I did M31 recently and had to realize that APP totally screws up the galaxy core: Not only the luminance was flawed (totally burned out core), but also the colour around the core was not as expected (green cast instead of yellow/orange). From the rejection map you can see what APP did to the core. Same happened to a set of 1 minute exposures that was supposed to HDR the galaxy core.
Despite offering somewhat sharper structures and less noise, the result from Deep Sky Stacker looks a lot more what I desired - see attached stacking results below (no stretch on luminance, only on colour layer to make APP's mismatch colours obvious).
When you compare the stacking results, APP seems to alter the point spread function of the stars (PSF) in a way that makes this function look more like a stovepipe hat, rather than a bell-shaped curve. This apparantly has also occurred on the galaxy core, overexposing it with steep transitions to the surrounding area. Is this really what APP is supposed to do?
Anybody else experienced this on a galaxy with bright core?
Altering the point spread function of the stars also raises the question, if APP's stacking result is any use for a deconvolution operation. I would say no.
My data for this stack is as follows:
100x 5-minute exposures, ISO1600
Nikon D750 DSLR (unmodified)
Esprit 100/550
EQ6-R, MGEN-3
I stack TIFF insead of the NEF, because I do not like the result of APP's DDP.
So the enclosed pictures resemble unstreched stacking results of 100 TIFF files.
When using NEF for stacking and using DDP in APP, the stars get way too large for my taste. I also dislike the colour results APP creates from the Nikon NEF.
And I am still using APP version 1.079 (maybe that is an issue?).
Thanks for your advice!
Chris
PS: To get a decent processing on M31 I combined the APP 5-min. luminance stack with the core of my 1-min stack compiled by deep sky stacker. I aslo used the colour layer from the 5-minute DSS stack, not APP. Final result here: https://www.flickr.com/photos/147135308@N08/50356400121/
However, I would be happier if APP did this job alltogether...
