AA7: no alignment, no star registration with sample data

Image processing, astrometry, photometry, etc.
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docMario
Posts: 2
Joined: 20 Apr 2020, 05:20

AA7: no alignment, no star registration with sample data

Post by docMario » 20 Apr 2020, 16:30

Hi,
i currently try to practice with astroart 7 sp3. I use the M42 example data downloaded from https://www.lightvortexastronomy.com/sa ... -data.html, however I have several problems:

- Auto alignment of Red, Green and Blue channel does not work... I was puzzled at first.. but then I discovered that the "find stars" function does not find any stars!
- If I start with RGB-composite and try to align the Luminance Picture (or vice versa), It's the same problem :(
Is this a problem of the example FITS data? Do I have to change my settings in AA7?

- Also, the Luminance Picture is larger than the RGB-composite (due to shifting and panning)... The LRGB-Function won't allow pictures of different sizes... what can I do?

please help:(

fabdev
Posts: 198
Joined: 03 Dec 2018, 21:43

Re: AA7: no alignment, no star registration with sample data

Post by fabdev » 20 Apr 2020, 17:11

Hi, as shown on the Astroart status bar, these are peculiar floating point images with the range 0.00 - 1.00 (?)

So the stars will have a S/N of almost zero. To align and/or collect stars you need to recover an acceptable ADU range, so after having opened the images press CTRL+N (or the button "X") to multiply for a constant, for example write 65000. Then click the status bar or press F4 to restore the visualization.

Now you can align them with the settings below:
about LRGB: at first you create the RGB image with the command Trichromy, then if the L has a different size, you need to Coregister the RGB image to the L image, before launching the command LRGB Combine.

docMario
Posts: 2
Joined: 20 Apr 2020, 05:20

Re: AA7: no alignment, no star registration with sample data

Post by docMario » 20 Apr 2020, 19:04

Thank you.
It worked. And I figured out how to prepare the differently sized color channels. yay! :-)

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