Mutli-nite integration

dave summa

I have a problem integrating subs (OSC) of the same target taken on different dates.  I setup and take down each session, so it's a given I am not perfectly aligned each evening. When I throw all subs in one hopper, I get something like the attached.  The corners (triangles) have a different background colors and DBE does not correct.  

I have tried to register and stack for each day, then create a mosaic of the different days.  This is fine, but the resulting image has a wonky shape and I must crop back to basically one of the day's dimension.  When I think about this, it may be a long road to the same outcome as "all in one hopper" approach.  With a lot more work.  Anyhow, it does not solve the problem.

I've tried GAME and masks, but the basic problem is the backgrounds are different and I do not know how to blend them to uniformity.

Would appreciate the help and even better, a video, sine I imaging this is a common enough problem.

BlockHead

HI Dave,

You might have illustrated a different common problem. The image you have attached is a JPEG image- likely saved from a linear image you had on your PixInsight desktop. You will need to convert it to a permanently stretched creature (non-linear image) before saving as a JPEG. 

-the Blockhead

dave summa

Ack, sorry.  The soft stretched version is attached.  I reviewed recent work, and this is near universal.  I suspect its moon/LP impact on background causing the differences, and the slight relocations causing the field rotation

BlockHead

Hi Dave,

OK. Now I see something. But I am not certain I understand, I do see a gradient in the image (it isn't major). Mostly green ... brighter towards the bottom left. This is something DBE should be able to take care of easily. If this is the issue, please make available the linear color image on some cloud solution and I can look if you want.

-the Blockhead

dave summa

OK, here's a link to the .xisf file on Dropbox.  It's in each corner, a triangle with the right angle in the corner of the image.  I have not been successful getting DBE to clear it.  Alas, my skills are not equal to this task.

Dave

https://www.dropbox.com/s/01o6xpr9ousvb5t/Reg_300s_DBE.jpg?dl=0 ;

dave summa

sorry, this is the link to the xisf file

https://www.dropbox.com/s/c91r59yrw6fccul/Reg_300s_DBE.xisf?dl=0 ;

BlockHead

Ah... the triangle parts are due to the fact you have combined images that were rotated. There are different S/N in these regions. There isn't a way for DBE to overcome this really. When I have multi-night data of this sort- I do not try to correct this. If I really wanted to make certain this isn't an issue...I would make certain the data is acquired without deviating from a 90 degrees rotation. (One or more of your frames is rotated at some in between angle).

So cropping the image is really the best solution. It is just really hard to "fix" this near the edges of images.

Otherwise, the strategy is that the original data needs to be acquired with more precision.

-the Blockhead