Mar 28 2026 APP 2.0.0-beta40 will be released in 7 days.
It did take a long time to have the work finished on this and it will have a major performance boost of 30-50% over 2.0.0-beta39 from calibration to integration. We extensively optimized many critical parts of APP. All has been tested to guarantee correct optimizations. Drizzle and image resampling is much faster for instance, those modules have been completely rewritten. Much less memory usage. LNC 2.0 will be released which works much better and faster than LNC in it's current state. And more, all will be added to the release notes in the coming weeks...
Update on the 2.0.0 release & the full manual
We are getting close to the 2.0.0 stable release and the full manual. The manual will soon become available on the website and also in PDF format. Both versions will be identical and once released, will start to follow the APP release cycle and thus will stay up-to-date to the latest APP version.
Once 2.0.0 is released, the price for APP will increase. Owner's license holders will not need to pay an upgrade fee to use 2.0.0, neither do Renter's license holders.
Hi,
I am seeing artifacts like you can see on the stars in this picture in my stacked image (scaled 2x, droplet size is 1.0). I was hoping someone more experienced than myself could see right away what this is and what might cause it. I used local normalization rejection on this image (but I have to admit that I don't know what exactly this does and whether it could cause something like this), my re-run without it is still in progress.
Thanks for your help,
Felix
Felix
I'm assuming since you mentioned droplet size that this is a drizzled integration. If that is so then I'll start with a few questions.
- Is this a bayer drizzle with a colour camera, or a normal (non-bayer) drizzle ?
- How many exposures and how many dithers were performed.
- Is the data undersampled (what arcsec/pixel ratio)
If I had to make a completely uninformed guess based just on the image and your post, I would guess that you may have done a bayer drizzle with too large a scale, too small a droplet size and not enough dithers. But that's just a guess.
The local normalization rejection is unlikely to be the culprit here.
I would also suggest that you do a non-drizzled test integration. If the problem goes away then you will know it is a drizzle issue. If it doesn't then we will need to look elsewhere.
JC
Thank you for the quick reply, JC.
The problem is gone after I reset all of the menues. One thing I did notice is that the normalization maps all had the stars visible, which I believe is not right.
The frames come from a mirrorless camera, taken with a 200mm lens (so quite undersampled if I understand correctly). I have 100 frames, dithered either every 3 or 7 frames (sorry, I changed the settings during the night and can't remember when exactly).
Unfortunately, I no longer have the settings of the menues before I reset them, so I cannot diagnose what I had done wrong (for posterity), but the immediate issue appears be solved at least.
Felix
I'm glad the problem is gone. I still strongly suspect it was caused by innapropriate drizzle settings.
Do you still want to drizzle the dataset ? With a 200mm lens your sampling will be somewhere around 6 arcsecs/pixel - so there may be some value in drizzle, as long as the parameters are appropriate. Drizzle is typically used either to fix 'blocky' stars or to upscale the image - perhaps to allow a crop that features a small section of the original image.
For a Bayer drizzle with a colour camera, I would suggest starting with a scale of 1.0 and a droplet size of 2.0 (I think the opposite of what you used), and ideally at least 30-40 dithers - more would be better. This should round the stars nicely. As the scale is increased, or the droplet size is decreased, the noise in the resulting image will increase - until eventually there will be drizzle artefacts that distort the image. These negatives can be reduced to some extent by increasing the number of dithers - even 80 to 100 dithers is not excessive.
If you want to test different drizzle settings quickly @mabula-admin has suggested that you change the composition mode in 6) Integrate from 'full' to 'crop' and select a small part of your image. This will integrate much more quickly.
JC
Hi Felix @edx,
Thanks John for assisting here 😉
I am glad that the issue is solved by resetting the menus. To me the problem looks like to aggresive outlier rejection in 6) Integrate. Could it be Felix that you were manually rejecting outliers and had the high kappa very low?
Mabula
