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Old 18-08-2013, 07:08 AM
mbaddah (Mohammed)
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Possible to fix out of focus stars in nightscape?

I took a series of images the others night for a timelapse and only realised after copying them to my pc that the shots were out of focus!
Is there any way of sharpening the stars or other forms of post processing to correct this? I'd hate to find out i lost hours worth of imaging Appreciate the help, thanks guys.
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Old 18-08-2013, 07:40 AM
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iceman (Mike)
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Not really.. sharpening will 'fix' it a bit, but it'll cause artifacts elsewhere.

Reduce the size to 640x480 and it won't look as bad.

Not much you can do unfortunately.
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Old 18-08-2013, 07:52 AM
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Quote:
Originally Posted by mbaddah View Post
Is there any way of sharpening the stars or other forms of post processing to correct this? I'd hate to find out i lost hours worth of imaging Appreciate the help, thanks guys.
Unfortunately you have only two choices-- keep a disappointing image that you have spent time on, or recognize that you have wasted time and invest more time in retaking the image.
Geoff
Although you could try deconvolution-- may help, but don't expect perfection.
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Old 18-08-2013, 09:11 AM
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jjjnettie (Jeanette)
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In photoshop,
Select - Colour Range - set slider to 25 - click on brightest stars, adjust slider to the right until most bright stars are selected - Select, Modify, Expand by 2 pixels - Filter - Other - Minimum, select radius of 1 pixel - Edit - Fade Minimum, adjust to 50%.
You'll probably have some dark halos to tidy up afterwards.
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Old 19-08-2013, 12:05 PM
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sil (Steve)
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A good mask, point spread function and erosion convolution in PixInsight can help.
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Old 19-08-2013, 01:07 PM
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Don Goldman totorial on the Liquify tool in Photoshop. Also Astro Tool software has a star shape tool that might actually work best.

Although best to trash it and work out a focus routine for out in the field imaging. Its easy to have focus off in a nightscape. Just leave autofocus on for starters and you'll get a mess.

Greg.
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Old 20-08-2013, 10:37 AM
mbaddah (Mohammed)
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Thanks guys for the tips i'll give it a shot this week and report back how it goes.
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Old 20-08-2013, 06:06 PM
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Go for it! But be aware that it will never be as good as if you'd nailed the focus in the first place. Software can make things look better, but it can never replace lost information.
Geoff
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