Common “knowledge” says that one can do narrowband exposures (HAlpha, Oiii) during full moons. I don’t know why that should be OK, since the Moon is scattering HAlpha light from the Sun as well as the usual RGB.
So, I did some exposures during full Moon, and some during no Moon. Here are the results. These are single raw images, with a Screen Transfer function applied in Pixinsight so we can see the image.
Click on an image to see the full image.
The Full Moon image in HAlpha has a lot of extra blur/nebulosity, while the image without the moon shows significantly better detail and contrast.
Not much shows up in the OIII images; apparently the California Nebula doesn’t emit much in the OIII range. The full moon version has a serious gradient, could be a function of where it was in the sky. The No Moon version has better contrast around the two stars.
Conclusion: it looks to me like the Full Moon still has a significant impact on the narrow band images.