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.
I'm having an issue with my flats. It started when I began taking flats with my Skywatcher 200P. Same camera and my RASA, the flats seem fine.
I'm using an ASI 2600 MC Pro, NBZ filter, Moonlite focuser. I use SGP to take the flats. 30,000 ADU and with the NBZ and with the 2600, the flats are about 6 seconds. I use a tracing light panel and a T shirt stretched (smoothly) over the scope.
I have attached an image without the flats, the master flat and an image after applying the flats. Interestingly enough, I had same issue with an ASI 294 MC attached to the same scope.
I suspect something is wrong with the flats acquisition or my processing in APP. A setting maybe???Â
I can't take the image train apart to make the darks until I figure this out....
Any comments on the image itself would also be welcome.....:-)
Any ideas?
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Thanks
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This looks like the flats are not matching the lights basically. Are you correcting the flats with a proper darkflat or bias (bias being 0.5 seconds of exposure, not much shorter)? What is the offset of both the lights and the flats?
Thanks for the reply.Â
As I said, the camera is an ASI 2600 MC P. I used "highest dynamic range" which sets the offset to 50. The lights and the flats were shot at that setting. With that said, I used 30,000 ADU as the target and with my present T shirt thickness, the flat exposure was about 6 seconds. Maybe I need to re-shoot at 2 seconds (take a layer out of the t shirts).
I haven't done the bias frames yet as I didn't want to take the train apart before I figured out the issue with the flats.
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Thanks again
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Lynn
Well, 6 seconds can be fine if that produces proper flats, target seems good though I would aim for higher, just making sure not to clip on the right-hand side. You do need to calibrate the flats with a bias or dark-flat though for it to work nicely.
High again,
So, I reshot the flats at 2.1 seconds and 25,000 ADU. Then I took the train apart and using SGP wizard, I shot 100 bias frames. I dumped the lights (two sessions) the flats and the bias frames into APP and let it process. Came out great, the big halo was gone. I'm not sure if the shorter flats or the bias frames fixed it, but I suspect it was correctly shot bias frames that made the difference.
From your comment above, are you saying that the flat ADU should be higher? If so, what would be a good target?
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Thanks
I think it more likely was the bias yes. Glad it worked!
Regarding flats, yes it's better to go for an ADU which is more to the right of the histogram (just make sure it doesn't clip). So 60-70% may work better, especially when you're taking flats at gain 0, for maximum dynamic range. This will ensure that there's way less chance of an issue at the lower end of the signal.
