Old 23-09-2020, 11:42 AM
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PKay (Peter)
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Barnard 33 in 4 panel mosaic

This is my first go at a mosaic, and I have to say, a fricken lot of work.

However a few issues were fixed by using a mosaic.

1: The Alnitak artefact:
By moving the star closer to the frame center, internal reflections inside the scope were greatly reduced.

2: Having a bright object close to a dull object:
I varied the gain, and number of subs for each 'mosaic tile' to compensate.

3: I can now revisit a portion (quarter) of the image to add more data.

Overall, 150 of 60s subs used.
60subs for the top right quarter (gain 140), and 30subs for each of the other 3 (gain 100).

All very confusing.

The resulting file is 1.3GByte!

And thanks all for the tips (and laughs) yesterday :-)
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Old 23-09-2020, 12:20 PM
Saturnine (Jeff)
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That is a pretty good result for your troubles, got rid of the artifact issue and has made for a nicely sized field. If I could add a critique, not that I'm qualified in any sense, maybe the field could have B33 just above the centre of the image, to help bring the Flame more into the frame. Just looks a little out of balance and unfortunately would cut out Sigma Orionis at the top of the frame.
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Old 23-09-2020, 12:27 PM
neurosis3000 (Reggie)
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Amazing image, Peter! Great work!
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Old 23-09-2020, 12:50 PM
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Sunfish (Ray)
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Very rich field. A great deal of clarity in the look of the image. A good looking mosaic.
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Old 23-09-2020, 12:53 PM
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Ripper of a job Peter, but what is going on with Alnitak? not the brightness
of course, but the sharply defined edge, I haven't seen that effect before,
but then I rarely use a refractor for imaging, maybe it is normal.


Last edited by raymo; 23-09-2020 at 12:57 PM. Reason: more text
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Old 23-09-2020, 01:28 PM
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multiweb (Marc)
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Nice one. That turned out well.
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Old 23-09-2020, 02:10 PM
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PKay (Peter)
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Isn't it funny...

I have worked how to use 'GradientMergeMosaic' in PI, but....
still can't work out to do those quote and reply thingys used down in 'Deep Space'.


So, thanks Jeff, Reggie, Ray, Raymo (I have no idea (in response)) and Marc.

Together we can wade our way through the technology.

If not for IIS, I would have given up long ago...
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Old 23-09-2020, 02:22 PM
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Atmos (Colin)
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It's come out pretty well, nice that you've been able to use a mosaic to remove the reflections
When I've been doing mosaics I've personally found that either APP does a better job of merging them together or if you want a free way of doing it, downloading Microsoft ICE. It does mean that you have to process all of the panels so that they're looking very close in colour calibration, black point and stretching but it tends to leave less artefacts than GradientMergeMosaic.
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Old 23-09-2020, 03:31 PM
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Anth10 (Anthony M)
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Top work Pkay. Really worth the time invested -
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Old 23-09-2020, 07:46 PM
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Great image Peter.

Well done with all the work you put in to that.

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Old 24-09-2020, 05:43 AM
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So beautifull. Peter, Congratulations!
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