Nick Outters (Royal Greenwich APOTY winner 2016...so no slouch) did and 89 hour exposure on this object with a TEC160
Suffice to say the TEC160 has 38% more collection area, no central obstruction and a significantly higher Strehl than a GSO 6" Newt.
see
http://outters.fr/wp/?p=7060
Yet your GSO image… taken from Melbourne…despite having less aperture and half the exposure time….has PGC field galaxies that are significantly deeper and better resolved (similar to a 24” CDK) and you’ve managed to capture fainter and tighter field stars.
Quite a remarkable feat.
I for one would like to know what your process is.