First of all let's say that I am not an expert of narrow band combination. I am trying to do something using RGB images taken from my n. 2 scope (an Acuter ED90 with a F 6.7 reducer and a modded Canon 600d) and O3 and HA that I take with main scope (Newton 250 F 3.9 Orion USA and a QHY 183M cooled). Second scope is mounted on top of main scope. Everything is driven by an Ioptron CEM 60 EC.

This image is the combination of:

1 - RGB Image with telescope 2

https://astrob.in/ubsx3r/0/

2 - O3 Image with telescope 1

https://astrob.in/v53nqx/0/

4 - HA Image with telescope 1

https://astrob.in/ra0l6a/C/

All subs were taken unguided using an Astroart script that keep the object in the middle of the frame for the whole night. Total exposures, including RGB, ha and o3 is around 30 hours. All frames have been collected from my home terrace and my bortle 8 sky.

For this image I have done composition fully in PS, combining red channel with 80% of ha, green channel with 80% o3. Alligning has been done manually in PS.

Thanks for looking.

The Crescent Nebula (also known as NGC 6888, Caldwell 27, Sharpless 105) is an emission nebula in the constellation Cygnus, about 5000 light-years away from Earth. It was discovered by William Herschel in 1792. It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 250,000 to 400,000 years ago. The result of the collision is a shell and two shock waves, one moving outward and one moving inward. The inward moving shock wave heats the stellar wind to X-ray-emitting temperatures.

It is a rather faint object located about 2 degrees SW of Sadr. For most telescopes it requires a UHC or OIII filter to see. Under favorable circumstances a telescope as small as 8 cm (with filter) can see its nebulosity. Larger telescopes (20 cm or more) reveal the crescent or a Euro sign shape which makes some to call it the "Euro sign nebula". (Wikipedia)