[g__day (Matthew)]

Hi Marc, saw you reply just now - thanks - yes focus inwards is selected; I am wondering if HFR is just a poor algorith with a subject like NGC 5139.

Run 4 - switching from HFR to FWHM gives settings of:

Luminance : 0
Red : 19
Green : -52
Blue : -94
Hydrogen Alpha : 0
Oxygen II : -33
Sulphur III : -99

Well that seems to have been the issue on this target - a small imaging run gave every filter is decent focus - so pack up astrolab and off to bed now!