I couldn't quite fit the Rosette nebula into my field of view, so rather than swap from my FLT120 to my Redcat51, I decided it would be a good time to try out a mosaic. This image was a simple 1x2 mosaic captured with Antlia 4.5nm SHO narrowband filters and my QHY268M monochrome camera. There's an almost 50/50 split between panels for total imaging time:
- Panel 1 = 8h50m
- Panel 2 = 8h25m
The OIII data was quite noisy, so it really helped waiting a month of rain and cloud until I could dedicate an entire night to capturing more. It was well worth the wait as the final OIII data was looking much better and the noise between panels was more balanced.
I used the "PhotometricMosaic" script from John Murphy to assemble each monochrome panel which resulted in three master lights (S, H and O). I then created the SHO image using the "NB Colour Map" script within PixInsight using guidance per Adam Block's YouTube channel. Hue and intensity values were assigned to each monochrome channel and a histogram transformation applied to control the amount of blend between the SHO channels. After running colour calibration, the resulting imaging can be somewhat considered as colour accurate (well, more so compared with traditional narrowband palettes!), which is great as you can see more natural red (Hydrogen) and blue (Oxygen) hues from the Rosette nebula. Sulphur is shown as light orange, which can be seen on the tips of Hydrogen gas but is more visible towards the centre of the image around NGC 2244 and NGC 2246.
I may have another play around with the process, but otherwise I'm really pleased with how this project has come out!
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