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 guys (and girls),
i need some help with making correct flat frames. First of all, what is the big difference between a linear and nonlinear histogram and how do i see if i'm using a linear or nonlinear histogram?
Second, when i used my dslr i never had issues maken flat frames aiming at the sky with a folded white thsirt on my telescope. however since i am using a cooled ASi294mc i can't get good flats anymore using the same technique…. i end up with gain 0 and -10C with a exposure of 0.5 sec max.... What is the best way (or a way) with this camera to get about 2-3sec flat frames. I do not own a LED screen or photobox to light my telescope….. Now i can't get rid of my dustbunnies…. 🙁
Thanks in advance!
Cheers,
Michel
Hi Michel,
Ahhh, flats, no worries they are the most challenging regarding taking calibration frames. But when they are ok, they help a lot. Stick with it, it might be frustrating but when you get it... sooo worth it. 😉
1. A linear histogram is what a camera sensor actually records in the amount of bits it has (e.g. 12-bit, 14-bit). Your monitor only has 255 values, so for you to be able to see the image at the expected brightness, you need to transform that linear signal into a non-linear one, usually some kind of logarithmic curve is fitted to the linear data. A DSLR on which you can show the histogram, usually shows you a non-linear histogram. This is a bit unfortunate for taking flats by looking at that, as the ideal situation for flats is to take them at about 50% of its linear histogram (this will make sure the sensor is well lit and not clipped either side). I always use Sequence Generator Pro also for my flats as it always works in 16-bits, no matter what camera I use. This is great because now I can always use its flat-wizard to just take the frames at about 30.000 ADU (~50% of 16-bit).
2. So it appears you camera is much more sensitive (good!). But you would need to cover up the telescope with more t-shirts or something like that. This is exactly the reason I like a flat-panel so much on which I can adjust the brightness.
@vincent-mod
Thanks for the clear explanation! Feels like i’m starting all over with the new camera type and options....
Guess i’ll be looking for a flatscreen then!!!
