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.
Immediately after completing integration, I did a save of the result. I chose to save in FITS format. I expected doing that would produce an exact copy of the FITS file that was automatically saved by APP after the integration process completes. I was surprised to find that the automatically saved file had a size of 365 MB, while the file I saved manually had a size of 91.2 MB.
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Why do these two FITS files differ so much in size? What information is present in the automatically saved file that is missing from the manually saved file?
Hi,
I'm not sure of this but I suggest you take a look at the FITS header info for the relevant files.
There is a header field NAXIS.
On the smaller file I suspect the NAXIS value will be 2, corresponding to a single channel (i.e. mono) image file with height and width dimensions.
On the larger file I suspect the NAXIS value will be e.g. 3, corresponding to a three channel (i.e. tri-color RGB) image file.
The AXIS values are given by NAXIS1, NAXIS2...NAXISn etc. corresponding to the number of data dimension. NAXIS1 & 2 will have values corresponding to the height and width of your image. NAXIS3 will have a value corresponding to the number of channels provided for in the image file, i.e 3 for an RGB image.
I suspect that following integration APP knows it is saving a single channel file but subsequently when the right hand SAVE button is pressed it assumes the file to be save is 3 channel, eg the saved file has provision for three channels as would exist once the Combine RGB process had been completed.
The FITS header info in the manual-saved image file has fewer fields compared with the auto saved file but the large size increase is due to provision for two extra image channels that presumably contain only null values.
Looking at my files I see the manually saved files are almost exactly 3x the mono files. In your case the size is 4x so maybe the NAXIS3 value on your larger file is 4 rather than 3, maybe Luminance.
Hope this helps answer your question
Mike
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