I recently attempted my first narrow-band image (Rosette Nebula) using my ZWO ASI1600MM-C camera along with ZWO 1st generation narrow-band filters. I did an interim processing of the data I acquired so far and the result is disappointing. The image shows false colours. For example, instead of bluish inner zone, mine is purple! I used 20 luminance frames and 30 SHO frames (10 for each) each 3 minutes. I know that I need to have more SHO data but I doubt whether this false colouring is solely due to relatively smaller amount of data or is it due to poor quality of ZWO NB filters. Actually when I see through that H-alpha filter it is more greenish than reddish. Have anyone else encountered similar issues with ZWO 1st generation NB filters?