Share:
Notifications
Clear all

June 24 2026 APP 2.0.0-beta46 has been released !

Improved internal memory configuration (lower ! memory usage), fixed beta45 startup issue, fixed Set Save Directory & 2-panel mosaics.

May 27 2026 APP 2.0.0-beta45 has been released !

Fully Multi-Threaded LNC, many improvements for the registration engine, platform upgrade, and further tuning of internal memory consumption and memory release back to OS.

Apr 14 2026: Google Pay, Apple Pay & WeChat Pay added as payment options

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.

 

drizzle problem

5 Posts
2 Users
1 Reactions
4,635 Views
(@jeroenm)
Red Giant
Joined: 9 years ago
Posts: 31
Topic starter  

Hi Mabula (@mabula-admin),

 

last week I started reprocessing the data of a 3-pane mosaic of the Horsehead Nebula and M42 I made last winter. Each pane is made up from RGB and Ha with a total integration time of ±16 hours per pane. Because the frames are undersampled and dithered I thought it was a good idea to use 2x drizzle during the integration: the stars were originally square, with the drizzle function they get circulair, which makes processing the stacks a lot easier. 

In just one of the panes (the one with M42; the other panes are fine) I got some strange artifacts near the border of the stack in all 4 channels when I use drizzle. This doesn't happen when I don't use drizzle. At first sight it looks like the original frames that make up the stack are dithered too well, but that's not the case.

 

In the screenshots you'll find a stack without using drizzle and a stack with 2x drizzle. Is there any setting causing this problem?

drizzle
normal

 



   
ReplyQuote
(@minusman)
Black Hole
Joined: 9 years ago
Posts: 251

   
ReplyQuote
(@jeroenm)
Red Giant
Joined: 9 years ago
Posts: 31
Topic starter  

@minusman

Thanks for your reply. I tried different settings in the integration tab and now I got a good result. Looks like the LNC settings and/or MBB setting are causing the problem. LNC level 1 with 3 iterations and a MBB setting of 8% was causing the "borders".  I decreased the MBB setting to 5% and didn't use LNC at all. Now the stacks are looking fine. In the screenshot the stack of the red data (top) compared to the stack with the artifacts (bottom).

Schermafbeelding 2019 08 27 om 12.49.38
drizzle

 


This post was modified 7 years ago by Jeroen

   
ReplyQuote
(@minusman)
Black Hole
Joined: 9 years ago
Posts: 251
 

Actually, it's not artifacts at all, it's dithering. This means that the edges of the pixels are not always served with imformation. That's why it looks so holey.
You need a lot of frames and it has to be dithered randomly to counteract the effect. My experience is at least 50-100 or more frames necessary to have an advantage over pixel interpolation.



   
Jeroen reacted
ReplyQuote
(@jeroenm)
Red Giant
Joined: 9 years ago
Posts: 31
Topic starter  

@minusman

Thanks for the answer. I certainly hoped to get a lot more data, but as usual the weather last winter was very bad here. I started this project (a 3 pane mosaic of the Horse Head Nebula up to M42 in R, G, B and Ha) early November last year. At the end of February when Orion was disappearing in the evening sky I almost used every single clear night to make this mosaic. I ended up with a total of 533 (good) light frames. Not nearly enough to use drizzle at my benefit. 



   
ReplyQuote
Share: