North Amercian nebula

A few days of clear nights left me with sleepless nights, sleepy days at work, and a lot of exposures on my harddrive. I decided I needed to exploit these nights as much as possible. I tried som filtered exposures. Like the propeller nebula previously posted.
On Friday, I was supposed to go out of town and to a darker place with some guys from my local astroclub. But the weather changed suddenly. And the area was wet with fog. So after waiting for a while for it to clear, I finally gave up. I packed up my gear, and on the way back, I decided to drive up to a spot on the hill overlooking the city. I had been there before to image a comet with another guy. The place was too close to the city to be really dark, but it as high enough to leave the fog and smoke of the city below. And this affected the light pollution. So the night sky was actually quite clear and relatively dark. I decided to try my luck at imaging with DSLR and my own "quasi-h-alpha"-filter that I have described here earlier.
I pointed at the North American nebula (NGC7000) in the constellation Cygnus. Trained the autoguider and set off a number of 10-minute exposures. Then laid back in the front seat of the car and slept for a few hours. The guiding was so-so, but adequate for me to get relatively round stars in the images. When I got home, I processed the images, and was pleased to see a clear and detailed image of the nebula. It probably could do with some more exposure to get more details out of the darker area, but for now, this experiment was successful. The filter I used is simply a deep red filter mostly used to take IR-photos in daylight. Since these are filters for photo-lenses, they do not come in 48mm sizes. The nearest was 46mm. So I ordered a 48mm-46mm stepdown adapter. This made it possible to attach it to any 48mm filter holders. There is, of course, some vignetting. But nothing that a good set of flats cannot compensate. It is NOT a substitute for a true narrowband H-alpha filter. But it is a much better alternative than nothing. And it is cheap. Very cheap.

Tech details : Pentax K5, ISO640, 18x10 min exposures. 0 darks, 0 bias, 20 flats. William Optics FLT98 @F/5 w/ WO AFR-IV. Celestron AVX mount. QHY 5II guide camera controlled by PHD2. Stacking in DSS, processing in FitsLiberator and PS.