RGB horizontal stripes

Image processing, astrometry, photometry, etc.
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brujo
Posts: 15
Joined: 24 Jan 2019, 20:41

RGB horizontal stripes

Post by brujo » 18 Jun 2019, 21:36

I am capturing LRGB with QHY174M Cooled camera.
Stacking Luminance files looks good, but
after stacking RGB images I notice some horizontal stripes.
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Image.png

einari
Posts: 44
Joined: 28 Jan 2019, 10:46

Re: RGB horizontal stripes

Post by einari » 19 Jun 2019, 08:55

Are you dithering ?
If not then you should.

There are ways to smooth those stripes but better to use dithering.

fabdev
Posts: 461
Joined: 03 Dec 2018, 21:43

Re: RGB horizontal stripes

Post by fabdev » 19 Jun 2019, 10:57

Also: are using an average of 8 or more dark frames? That is camera noise, there are still some hot pixels.

brujo
Posts: 15
Joined: 24 Jan 2019, 20:41

Re: RGB horizontal stripes

Post by brujo » 19 Jun 2019, 13:04

Yes I am dithering, after the green filter I have switched it on the red filted, but same results.
Using PHD2.
Also have about 30 dark frames.
Maybe it's just that "colored" images needs more files.
In this case I have made 60 images of 60 seconds (well it is one hour..!).
It's strange because with luminance filter it looks so much better.

einari
Posts: 44
Joined: 28 Jan 2019, 10:46

Re: RGB horizontal stripes

Post by einari » 20 Jun 2019, 07:12


fabdev
Posts: 461
Joined: 03 Dec 2018, 21:43

Re: RGB horizontal stripes

Post by fabdev » 20 Jun 2019, 13:27

The luminance has a dark border on top, this means that dithering was working and there is some shift between the images.
The green image has not the border. Maybe dithering was disabled? Verify that there is some shift in the green sequence.

Verify also that the dark frame are updated (taken in the last weeks, at the same temperature).

brujo
Posts: 15
Joined: 24 Jan 2019, 20:41

Re: RGB horizontal stripes

Post by brujo » 20 Jun 2019, 22:38

Have repeated once again.
Luminance without dither and Green with dither.
And the problem remains.
I'm confused..
After making a new set of green frames i see that the solution is to make a lot more coloured images than luminance.
2 hours of green images are looking better

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