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.
Hi there,
I hope you are doing great.
I wanna have some questions regarding Dark Frame Scaling.
I am a DSLR user and do Astro and Deepsky Astro for enjoyment. I know the limitations of uncooled DSLRs.
I understand all the basic concepts needed for this hobby. As summer here, DSLR sensors produce a lot of thermal noise and hot pixels. During winters, sometimes I never take dark frames but dither manually (i have a star tracker, but I can do it on both axis) as the temperature was 5-15 degrees below zero. I try to dither after every few frames no matter the season I shoot.
But now its summer/rainy humid season and now the temperature is approx 28C to 35C.
So, the point is, if I make a master dark for 50-100 frames with 5 min subs at ambient or room temperature (between 25-30C/ different night/day, can I use them for the whole summer season?
If yes, then what ISO should I pick? Does it matter for dark frame scaling? Or will it work if I make a master dark from my all darks that I have taken so far at different temperatures, seasons, sub-length, and ISO? what would be a good strategy?
Please share your experiences.
TIA
Hi Aditya,
yes you can use darfkrame libraries. As a rule of thumb, noise level doubles each time when temp raises by 7C on DSLRs. However, this relates to the sensor temp (which is more constant once the Cam is working a few min), not the environmental temp. The usual advise is to have masterdarks for each 2-3C steps, in Your case You could get waway with 28C, 31C and 35C and pick the closest. I think the scaling only works well with ISO & exposure time changes, which behave more linear, not with temp which is very non-linear and strongly depending on the Cam. Note: You need to renew the libraries once or twice every year.Â
Clear skies,
Jochen
@aditya_photos Adding to Jochen's excellent answer: dark frames need to have the same ISO as the lights and preferably also the same exposure time. If the exposure time is different then you'll need bias frames of the same ISO as well.
Wouter
