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,
Can you please guide me to best practices when for my queries below:
- When shooting with dual band filters, do the darks, flats and biases need to be taken with the filter as well?
- When creating master files and BPM, does the debayer have to be set as per the filter used? (e.g. RGGB, Ha-OIII color, force CFA)
- Different nights, means different calibration files. Do i keep each night separate or can i create master files by integrating all the different master flats, darks and biases as i acquire them?
Thanks
Raed
For sure people, more experienced than me are going to answer and they will correct if I mention any wrong information.
1- Darks no need to be taken with any filter, but flats and biasses. Filters "filter" specific kind of lights and since darks have to be taken covering the scope there is zero light to be passed or cut, so no sense to use filter in dark frames. On the other hand, every filter have a specific spectrum and affect in different ways so flats and biasses need to be taken with filters.
2- BPM is a map of defected pixels, not related to filters. Defect pixels can not be "repaired" by using any filter.
3- You do not need to take darks, flats, biasses every night. You can use darks and BPM 1-2 yeras, then reneweng them is a good idea. But flats are different subject. You need to take flats every time when you change any optical condition eg.:
a) When you change filterwheel (different brand different size etc. filterwheel)
b) When you change scope
c) When you change flattener/corrector
Otherwise you can use your masters.
Regards,
Volkan
What @volkanovun says. With one remark. You take bias as darks, just with a very short integration time. No need to do that per filter. And you can use bias for a long time, just as your darks and BPM.
So, the only calibration files to be done with filters are the flats. A flat with a NB filter will differ from a flat with a UV/IR filter. First of all because of the fact that there is different dust etc, but also because the transmission of a NB filter differs from centre to the edge because of the angle of the light and the bandpass shift in NB filters as a function of the angle. This is of particular interest with a fast system. For simplicity: if you change anything in your optical path, take new flats. And even when nothing changed...there might be new dust. So, it is a good habit to take flats every imaging session.
Thanks for the replies. Much has been gained. Just one more thing when it comes to calibrating the master flats (now I know it doesn't matter for the darks and biases 🙂 ), do the settings in tab 0 have to reflect the algorithm to use based on filter? Or this would only make sense once processing the lights?
I guess it is obvious to say the one should not stack flats of different sessions and filters.
Thanks for the help. Much appreciated.
Adding to the excellent advice given by @volkanovun and @annehouw, you also need to take new bias and darks if you change the ISO/gain, the temperature of the sensor or both. If you are using a cooled camera then you can reuse the bias and darks by always shooting at the same temperature (for instance -5° or -10°) and gain (for instance unity gain or a gain of 100 for modern ASI cameras). If you use a DSLR then it is much more complicated since those cameras almost never have active cooling (unless you modified it yourself).
Wouter
Thanks everyone for your inputs. enjoying APP greatly so far, even more so this hobby despite the frustration 🙂
