Channel assignment and coloring and narrowband datasets

Unique to StarTools, channel assignment does not dictate final coloring. In other words, loading, for example, a SHO dataset as RGB, does not lock you into using precisely that channel mapping. Thanks to the signal evolution Tracking engine, the Color module allows you to completely remap the channels at will for the purpose of colouring, even far into your processing.

As is common practice in astronomy, StarTools assumes channels are imported in order of descending wavelength. E.g. the dataset with the longest wavelength (e.g. the light with the highest nm or Å comes first). In other words, the reddest light comes first, and the bluest light comes last.

In practice this means that;

  • When using visual spectrum datasets, load red into the red channel, green into the green channel, and blue into the blue channel.
  • When using triple channel narrowband datasets such as Hubble-like S-II + H-alpha + O-III (aka "SHO" datasets), load S-II as red, H-alpha as green and O-III as blue.
  • When using a duo/tri/quad band filtered dataset, load H-alpha (which is possibly combined with the neighbouring S-II line depending on the filter) as red, and load O-III (which is possibly combined with the neighbouring H-beta line depending on the filter) as green.

In any case, you should not concern yourself with the colouring until you hit the Color module in your workflow; as opposed to other software, this initial channel assignment has no bearing at all on the final colouring in your image. Please note that failing to import channels correctly in the manner and order described above, will cause the Color module to mis-label the many colouring and blend options it offers.