Colorize red to IR images

Although the author does not have much experiences yet, he has tried the following two methods.

Compositing with images using the H-alpha filter

This method uses H-alpha emission lines in the red band, which is also less light polluted, to colorize the HII region to make it stand out. Here is an example of M33.

Compositing with a low-resolution color image

This one uses normal color images ( captured by a one-shot color camera is fine) as RGB channels, and red to IR images as L channels. However, since it is difficult to obtain high-resolution images in light-polluted areas, capturing a large number of binned, low-resolution images would allow us to gain some signal-to-noise ratio in light-polluted areas.