whzzz28
04-09-2012, 11:16 PM
Using PixInsight to LRGB combine and i notice that when i do combine, some stars disappear.
Screenshots attached are an example.
The first shot is an RGB combine. Notice the slightly greenish blob towards the middle-bottom-right. No idea if its a star or not, could be 2 stars, a galaxy, a something or my tracking was wonky.
Now take a look at the 2nd screenshot.
This is after combining the LRGB.
Its gone, or is it? If you look really closely you can see a very light green, almost noise like area where it was. I think this is a left over though, so probably gone.
So i checked my lum stack.
It's not there either...
I would of written it off if it was visible in lum but not in RGB, but to not be visible in the lum data?
Chromatic noise reduction was not turned on when combining and i went back through and removed any morphological transformations i applied to both lum and RGB stack. I also opened my raw lum stack and did a screen stretch then took a look. Not there in the lum data at all.
Interestingly, if i look at the other stars that disappear, they took look similar in color and style (blobby not round and slighty green).
There is also some significant reduction in star sizes on random stars (not the very brightest) between RGB and lum, but i am putting them down to possibly incorrect focus distances between filters.
Any ideas or thoughts?
Im not overly concerned, just interested in what is happening and why.
Cheers.
Screenshots attached are an example.
The first shot is an RGB combine. Notice the slightly greenish blob towards the middle-bottom-right. No idea if its a star or not, could be 2 stars, a galaxy, a something or my tracking was wonky.
Now take a look at the 2nd screenshot.
This is after combining the LRGB.
Its gone, or is it? If you look really closely you can see a very light green, almost noise like area where it was. I think this is a left over though, so probably gone.
So i checked my lum stack.
It's not there either...
I would of written it off if it was visible in lum but not in RGB, but to not be visible in the lum data?
Chromatic noise reduction was not turned on when combining and i went back through and removed any morphological transformations i applied to both lum and RGB stack. I also opened my raw lum stack and did a screen stretch then took a look. Not there in the lum data at all.
Interestingly, if i look at the other stars that disappear, they took look similar in color and style (blobby not round and slighty green).
There is also some significant reduction in star sizes on random stars (not the very brightest) between RGB and lum, but i am putting them down to possibly incorrect focus distances between filters.
Any ideas or thoughts?
Im not overly concerned, just interested in what is happening and why.
Cheers.