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

Bi-monthly release with minor bug fixes and improvements

[Solved] Fits viewer freezes (crashes kstars) with auto stretch

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BTW, if you've gone as far as compiling on your odroid and running with QtCreator, you'd do me a big favor if you could also undo you change, run valgrind in qtdreator and watch the crash, and send me all the valgrind output. See doc.qt.io/qtcreator/creator-valgrind-overview.html Would want to make sure valgrind is running its memory checker, but I think it does that by default.

Thanks,
Hy
4 years 4 months ago #46113

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Replied by Andrew on topic Fits viewer freezes

This is a tangent, but you appear to have some issues in your optical train to look into. There's coma and plenty of vignetting. Maybe too much focal reduction? And there are prominent diffraction spikes that shouldn't be present with an SCT. That can happen with cabling for hyperstar, or worst case a scratched corrector plate, filter, focal reducer...
4 years 4 months ago #46118

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Replied by Jerry Black on topic Fits viewer freezes

Thanks for the feedback, yes I'm not sure what's going on with this, but it's likely all my doing... I'd appreciate any adivce.

The SCT is an OLD hand-me-down 10" Meade which I have attached an 2" extension tube from a slightly newer 8" Meade LX200 with no focal reducer between to a Nikon Z7. I'm not sure why I get that vignetting. The coma I presume is a normal reflection of this SCT's quality.
For the diffraction spikes, I don't really know either, I assumed it was a side effect of a 120 sec. exposure at ISO 12800 :)

I have had advice that that ISO was crazy, I was just seeing what a larger number of shorter high ISO exposures might do when combined. Here is the result (for better or worse)
www.dropbox.com/s/o2pwgnsgwhsk6vd/light_..._sub_div_ST.jpg?dl=0
not quite as clean or sharp as those refractors the imagers around here have.

4 years 4 months ago #46120

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Replied by Andrew on topic Fits viewer freezes

Ok. I'll just quickly say that from a little sleuthing I found that the older Meade SCTs require their F/6.3 focal reducer/field flattener to correct for these aberrations. Their newer models feature 'advanced coma-free optics' and do not require one.
As for the diffraction spike, inspect all optical surfaces carefully. Also check your secondary mirror collimation from time to time, especially if you are transporting the telescope.

Clear skies.
4 years 4 months ago #46152

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Replied by Jerry Black on topic Fits viewer freezes

Thanks, Ihoujin, my Meade focal reducer is missing/hiding at the moment. I may have to replace it.

4 years 4 months ago #46157

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Replied by Hy Murveit on topic Fits viewer freezes

Jerry and I collaborated on fixing the bug Jerry mentioned at the start of this thread. The fix is now in the latest code if you 'git pull' it.
Thanks Jerry!
The following user(s) said Thank You: gehelem, Alfred, Jerker B
4 years 4 months ago #46164

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hi
same problem here with ASI183MM :
using autostretch makes kstars crash
This fix solves the problem
thank you Ihoujin and hy

Gilles.
4 years 4 months ago #46353

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