|
Binning 2x2 approx doubles the signal to noise ratio of the same length exposure. It comes at the cost of less resolution as 4 pixels are now averaged into one.
A common practice is to shoot luminance at 1x1 binning (ie each pixel counts only as one) and rgb each at 2x2 binning as their usually is less detail in colour so less resolution is not as important as getting the signal quickly.
If seeing is poor 2x2 binning on luminance makes more sense as the seeing will limit the resolution anyway so no loss.
When imaging galaxies though and you want max resolution binning both luminance and RGB can make sense. You can then add a desaturated rgb combined image into your luminance for a bit of extra signal.
Binning faint Ha objects like the Helix can also make sense to reduce the time to get the signal up. I find binning Ha on my CDK17 gets great results. It can also help reduce vignetting from light pollution as the signal becomes stronger than the background more eaily etc.
Greg.
|