Creating every synthetic narrowband image palette from One Shot Colour (OSC) RGB images

Creating every synthetic narrowband image palette from One Shot Colour (OSC) RGB images using the PixInsight Toolbox Script CreateHubblePaletteFromOSC. 

We have previously discussed the use of this script with respect to creating a synthetic Hubble Palette SHO image. I use the term ‘synthetic narrowband image palette’ because, coming from an OSC RGB image, all of the necessary Ha, SII and OIII data are simply not available as separate (or separatable) colour channels as they are in true narrowband or (Ha, OIII) and (SII, OIII) pairs of dualband images.

The CreateHubblePaletteFromOSC script takes an OSC RGB image and produces reasonable approximations of all of the narrowband palettes with the exception of SOH (which I feel must be an oversight). It also produces an approximation to the HOO two element palette.

Fortunately there is a Utility script called Swap channels that allows us to take an ‘OSH’ image produced by CreateHubblePaletteFromOSC and swap the R and G channels to produce an ‘SOH’ image.

Whilst many astro-imagers regard PixInsight or Siril etc to be ‘one stop shops’ for all of their image processing, my approach is to use whatever software I feel is most appropriate to my workflow, which includes a number of programs such as the Gimp, Neat Image and Photoshop CS2.

As previously, we start with an OSC image of the Elephant trunk nebula captured using AstroDMx Capture, through an Altair Starwave 60 ED refractor with an 0.8 reducer/flattener and 2" magnetic filter holder with an Altair 2" Quadband filter, and an SVBONY SV605CC OSC 14 bit CMOS camera. 

It is best to work with starless images for processing nebulae and this was done with StarXterminator in PixInsight.

Invoking the StarXterminator Procedure

Starless image an a stars image produced

Launching the CreateHubblePaletteFromOSC script

Producing a 'HOS' image for example

Synthetic narrowband images produced by the CreateHubblePaletteFromOSC script

All of the starless, synthetic narrowband palette images were saved along with the stars image.

Using the Swap channels script on the 'OSH' image produces an 'SOH' image which was saved

The starless images were stretched by the same amount, below are three example

The images were denoised using the same settings in Neat Image as the three images below illustrate

Table showing the synthetic palettes in the montage of images below with the OSC RGB original at the bottom right

Montage of synthetic palettes as shown in the table above

The CreateHubblePaletteFromOSC Toolbox PixInsight script produces sufficiently good analogues to narrowband palettes that allow an imager using an OSC camera producing RGB images to be able to present their data in a way other than simple RGB.