Thoughts on which imaging rigs to concentrate on

[Gina]

Done that now to combine colours    Colour-Combining with PixelMath

[Gina]

Trying this mix :-

Quote

R/K  0.4*Ha + 0.6*SII
G  0.4*OIII + 0.3*Ha + 0.3*SII
B  OIII

 

[Gina]

Here's the result.  Bit wishy-washy and needs some tweaking.  I know I should process in PixInsight which I will later but for now I'm going into Photoshop where I know what I'm doing.

[Filroden]

Looking good. You still have a gradient in one of your images by the look of it and some additional processing to make it pop, but that's the start of a nice SHO image!

[Gina]

The SII is poor and I think dragging the result down.  I need either to be more selective in the SII images or just go for bi-colour.  Ideally I want more SII subs.  Maybe I should turn the camera back to this orientation and take more SII H&S subs before these DSOs get too far west.  I have some 240s SII subs which I haven't used.  Maybe I should pop out and cover the lens and take some matching darks.

I tried to drag something out in Photoshop but I think I'm scuppered by inadequate starting image.

[Gina]

Been looking back through this thread and I see I decided at the time that the SII subs were useless   Not sure whether these were taken with a gain of 440 or 500 - don't seem to have noted that down.  I think my best bet would be to try again next time we get some clear night sky with a gain of 600.  This seems the best gain for faint nebulosity.

[Gina]

Think I might try a different set of formulae in PixelMath.  This one uses less SII so might be better.

Quote

R/K: 80% Ha + 20%SII
G: OIII
B: 85% OIII + 15%Ha

 

[Filroden]

5 minutes ago, Gina said:

Think I might try a different set of formulae in PixelMath.  This one uses less SII so might be better.

 

I intrinsically like this one as it's trying to mimic the Hb in the blue channel using a fraction of the Ha data.

[Gina]

No good - comes out all pink and green   OK magenta actually.

[Filroden]

I think your idea of bicolour until you get some more SII might be the right call.

[Gina]

Yes indeed and here it is - just as screenshot in PI.

[Gina]

Blummin' marvellous...  watching ASC I noticed that the sky had half cleared where I wanted to image so went out and slackened and removed focus gear, slackened mount and rotated camera back to H&S orientation, reclamped mount and put focussing gear back on.  Removed lens hood and replaced it with the dew shield.  Then I opened the roof only to find thin cloud covering the moon and all the rest of the sky!!!

[Gina]

Post processing in Photoshop.  Screenshot of image plus histogram.  Getting the histograms matched for best image was tricky.  I'll post the full resolution and image depth shortly.

[Gina]

PNG version.

[Gina]

I would like to thank the admin/mod who moved this thread to the Imaging - Discussion forum which is where it now belongs.  I have forked off another thread in the DIY Astronomer forum to cover the DIY aspects of my imaging rig called "Mountings and Controls For Widefield Imaging Rig".

This thread will now cover imaging aspects only.

Edited December 7, 2016 by Gina

[Gina]

Don't know when I shall see any clear night skies - fog, fog and more fog!!   Possibly Sunday night if the forecast is anything to go by.  Meanwhile, still oodles of data to process... except that I need a rest from it   So I'm looking at the next mods to the rig - see the other thread.

[Gina]

From a Hubble thread and relevant here :-

25 minutes ago, PatrickGilliland said:

HI Gina

SCNR adjusts the green to a more likeable palette range - HLVG kills the green from recollection.  So SCNR maintains data in correct preferred colours rather than removing your hard earned data.

I like

R=s*.76+h*.24

G=h*.85+sii*.15

B=O

Then SCNR at about .9.  You can tweak colours by adjusting the percentages applied per channel and tweaking SCNR.  You have full control.

Why green? - well thats the colour it combines at you then need to shift into the correct palette.

Paddy 

Thank you Paddy - I'll try that   So much simpler that the process I used in Photoshop but yet to produce as good a result but I'm sure that's mainly a matter of getting the best formulae.  I never really understood what I was doing in Photoshop - just followed a manual process.  I understand the colour mix process here

[Gina]

Trying some imaging tonight as it's reasonably clear ATM.  It was misty earlier but the mist seems to have descended to lower levels and we are above it here.  I can see it lying in the valley below.  Trying to capture the Heart and Soul in SII as I'm lacking that data.

[Gina]

The sky now seems crystal clear to the eye but I can't see much of the nebulae in SII.  Quite good clarity and seeing earlier when I set up focus too.  Here's a 60s g600 t-30C sub.  Still nice tight stars but little sign of the nebulosity.   Just have to see what integrating 100 odd subs will give.

Edited December 11, 2016 by Gina

[Gina]

Put tonights subs through Blink and dumped clouded out frames leaving 99 which I'm now processing in BPP.

[Gina]

Hmm... into the registration stage and it's throwing up a lot of errors - can't match stars...   Or not enough matches.

Edited December 11, 2016 by Gina

[Gina]

Trying a different reference frame.

[Gina]

No joy   Think tonight's run is useless but I'll have another look at the subs.  Clouded over now so that's that for tonight.

[Gina]

Just been out and shut down - closed roof.  Extreme dew tonight - wet everywhere except on the camera lens so my home made dew shield plus some warmth from the gear kept the dew off the lens   I expected to find I would need a dew heater but seems not.  Switched the dehumidifier on to remove the damp from the air and equipment surfaces.

[Filroden]

10 hours ago, Gina said:

Hmm... into the registration stage and it's throwing up a lot of errors - can't match stars...   Or not enough matches.

Your background looks quite bright so PI's staralignment might need a different detection threshold to get enough stars. I've never had to change those parameters before but I think they are covered in Warren's book.