Sky background normalisation

[Obititi]

Hello,
Hope you will be able to understand my English.
I use now Sharpcap for several months and I wonder about a fonction we could call "Deep Sky Backgroung normalisation".
Wouln't it be possible to create a function where :
- we could select an area in the background sky
- Sharpcap could create a layer by copying this area everywhere in the layer
- And substract this layer in the liveview, the same way it is done with a dark.
Do you think it could be a good idea ?
And possible ?
Thanks a lot.
Thierry.

[admin]

Hi Thierry,

If you are thinking of just making the whole picture darker by subtracting a constant amount from every pixel, then there's really no need to do that because you can already adjust the black point in the live stacking histogram to basically make the software treat your set value as being the 'zero signal' value.

There is a more sophisticated way to do this – the suggestion has been made elsewhere to add a function to remove this sort of background brightness even if there is a gradient in that background across the image (for example more light pollution on one side of the frame and the other). This function has been suggested elsewhere on the forums as 'background gradient removal' or something like that. I have it on my list of features that I want to add in the future (after SharpCap 3.3 is done).

Cheers, Robin

[Obititi]

Thank a lot for your answer.
What i think about is not only black level, i thought it could also adjust colors, as you can find it in Siril if youn know it.
The black level doesn't modify colors ?
There is a litle lake in my question :
I suggested to substrac the layer from the picture but we might add a standard background in the proccess :
- clic in the background
- copy the area everywhere in a layer
- remove from this background layer a standard background deep sky.
- remove it from the picture.
Somewhere, it could adjust the white balance, and remove a big part of light pollution ?
To easy i suppose ... you would already done it if it would be good ...
And i don't know how is managed the bayer matrix ...
At this point, i don't think about gradient, a really more sofisticated proccess ...
Again, thanks a lot.

[admin]

Hi,

thanks for explaining again, I think I understand a bit more now - I will think about how this might work.

Robin