This was a backup target. I wanted to capture M16 (SHO), but this is available only about 3 hours/night and the area is almost always cloudy and foggy. Still, I kept the camera in position for it. Unlike this, the Crescent Nebula (NGC6888), is available all night, at high altitude ( it's less affected by fog).
However, during five nights, I barely collected 13 hours exposure. I've waited even until two o'clock for the sky to clear. The stacks were noisy (I used unity gain)-I would have needed more exposure time.
I tried HOO combination in linear state and also with stretched stacks. Each one has its advantages.
Setup: newt
Clear skies!
