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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

How to use the Focus Module to focus on a galaxy

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Hi,

what I did up to now is to focus manually or with auto focus on a star, which works fine!
But which settings to focus on a great object like M31 galaxy?

Sub frame or full frame?
Focus the center of the galaxy or the stars at the edge of the galaxy?

Regards,
Armin
4 years 5 months ago #44718

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What I do is slew to a good nearby star, then use that to focus, then back to the main target (using the alignment module).

I use my bahtinov mask, since my internal focuser is not currently working for me (the donut issue).
4 years 5 months ago #44720

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To help avoid confusing the focusing star detection with the faint fuzzies, you can try full frame focusing with the central area excluded
4 years 5 months ago #44724

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@ Megiddo: Which donut issue do you mean? Because I also see donuts after auto focus!

@ Ihoujin: What are the settings for " full frame focusing with the central area excluded"? Maybe you could provide a screenshot?
4 years 5 months ago #44763

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You can see it in this thread: indilib.org/forum/focusers-filter-wheels...id-the-opposite.html

The focuser module starts by moving in/out and if it does it too much and creates the donut, it gets lost. I've tried pretty small step values, which makes me think I need to try even smaller steps. Tonight I'll try 5 or something tiny. (assuming clear skies)
4 years 5 months ago #44772

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I can't offer screenshots at this time, but you will find among the check boxes in the focus module one called full frame. Then there are two fields to enter % of inner and outer fields to exclude. They are used to avoid confusion in the center and stars with aberration in the corners.
The following user(s) said Thank You: Armin Prohaska
4 years 5 months ago #44785

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Thank you Ihoujin!
4 years 5 months ago #44788

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