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The thread demonstrates the value of forums like this.
I've learnt 2 lessons today from the comments posted.
Firstly, I've started playing with the Masked Stretch tool in PI - what a great feature! I have found in the past that applying a STF stretch and moving it to HT, bright features are blown out. This works well to keep it under control.
I have so much to learn about processing with PI! But its good to ave some tips.
The other comment from Dave (and I think also Ray) was that the stars looked a bit blown. I've tracked it down to my focussing.
I have the Hendrick electronic focussed on the PW which I operate through FocusMax. As I have a permanent set up, I leave everything on - PC, focuser, mount, camera etc. When I run a VCurve set in FocusMax and then focus, peak focus was initially around 4,000 microns out on the focussed. I noticed that the focuser was last night was reaching focus at about 7,000 microns. That looked odd. So I reset the focuser ie ran it all the way in, reset that as 0 microns and focussed again - focus was just under 4,000.
So what is happening here? I suspect that the focuser loses its way over time - so that the place it believes it is located at doesn't match the actual position. So over time, the focus drifts.
After rehoming the focuser, I found the peak FWHM for my images dropped from around 3.5 arc seconds to about 2.9. Not a huge amount but it makes for sharper stars.
I'd be interested in hearing if anyone else has experienced this. Will send an email off to PW too.
Pete
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