Cometary nebula CG 30-31

CG 30 and 31 are known cometary globules that are part of the extensive Gum 15 nebula in the constellations Puppis and Vela. This complex is relatively rich in dark dust clouds.

The material available in TL is quite good, but achieving a good result requires a lot of work. This was one of the most challenging projects I've tackled so far. I have processed the image in PI and AfinityPhoto.

My image is a composite of (LHa)(RHa)GB.

I chose the L and Ha combination for two reasons. First, it enhances the L channel with the bright parts of the nebula visible in hydrogen, and second, it allows me to eliminate background irregularities in areas where the nebula is not illuminated.

Processing the Ha channel was quite a challenge due to its relatively low SNR ratio. First, I had to remove the noise and thus the deconvolution does not work properly. It left the hydrogen image very blurry. So I decided to combine the L and Ha channels with ImageBlend minimum and maximum filters. It allowed me to eliminate background problems in the dark parts of nebula in L band and enhance the luminous areas with bright hydrogen portions. Advanced masking in AF was necessary.

Removing the halo around bright stars was also a big challenge. The MMT method came in handy. By removing several layers I was able to eliminate the stellar halo and after that I recompose the images. I also added the Ha channel to the R channel.

Stars has been stretched using the SetiAstro StarStrech script. I have used the RGB star to blend to final image. All the processing (except BXT) I have done with starless images .

I have created almost 18 GB of additional images, mask and composition to reach the final effect. I hope you like it.