This really was a pig to process and trying to get the right colour when there is so much Ha present, very little OIII and good amounts of SII.

It took 4 full attempts in PI to get it right and I ended up processing it completely differently that I would other NB images

I ended up having to balance the channels with Pixel Maths in PI and finally settled on the HSO pallet, I am quite pleased how the stars came out.

In this instance I think perseverance paid off and I don't think with my skies that I could achieve much better.

As usual, here is the Bumf courtesy of Wikipedia: -

Sh2 -173 is a visible emission nebula in the constellation of Cassiopeia .

It is identified approximately 3 ° to NNE of the brilliant β Cassiopeiae (Caph), the star that represents the westernmost part of the "W" of Cassiopea, and is located south-west of the 12 Cassiopeiae , a white-blue star of fifth magnitude . Given its strongly northern declension , its observation is possible especially from the regions of the northern hemisphere , from which it appears circumpolar up to the subtropical latitudes, while from the southern hemisphere its visibility is reduced and limited to tropical regions only.

It is an H II region with a diameter of 77 light years , located at about 2700 parsec (about 8800 light years) away. It is located on the Perseus Arm , one of the major spiral arms of the Milky Way , at the OB Cassiopeia OB5 association, which includes some open and nebulous clusters , such as Sh2-172 and Sh2-177 , in contact with a large superbolla with a 380 parsec diameter, created by the stellar wind of the mass stars of the association. It contains a large number of young stars, of which there would be at least 7 of the main ones responsible for the ionization of the gases , the hottest of which is listed as BD + 60 39, a blue star of spectral class O9V; would be part of a large star-forming region located near the Cas OB5 association, to which the nearby nebulae, as well as the NGC 103 open clusters and the KR 98 radio wave source are connected, as well as the LDN dark nebula 1282.