How to avoid oversaturation in Livestack final images

Discussions of Electronically Assisted Astronomy using the Live Stacking feature.
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GoFraRo
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Joined: Thu Sep 16, 2021 8:45 pm

How to avoid oversaturation in Livestack final images

#1

Post by GoFraRo »

Hi,

triggered by a question in another forum, I came back to a problem I was faced with a couple of weeks ago.
After capturing and saving M13, I found strange pixels in the core of M13 in the eventually saved Fits file.

The other guy reported a similar issue with his image. 60/330 Apo, ZWO ASI294MC, SC Livestack, but no further details
In my case, TS Photoline 60/360, Neptune-C, SC Livestack, 150 x 20sec, Gain 250, Offset 150, saved as 16bit Fits

From my understanding, the pixels in the core seems to be oversaturated. Or am I wrong ?

I know so far, how to avoid oversaturation with single captured images (lower gain, shorter exposures, binning?, different cam with larger pixel, etc.).
But how can I avoid it generally in Livestack ?
Any suggestions ? Are there any thresholds that can be set ? Pitfalls to avoid ? etc...
Thanks a lot in advance.
Regards and cs
Gottfried
M13histo.jpg
M13histo.jpg (74.7 KiB) Viewed 1328 times
TS Photoline 60/360, TS Photon 150/750 Advanced Newton, Bresser 90/500 & MC 127/1900, ZWO ASI120MC-s, Player One Neptune-C, Altair Hypercam 294C Pro, SVBONY SV165 Guidescope, iOptron Cube Pro & CEM25P, Bortle 4, Germany-northwest region
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Re: How to avoid oversaturation in Livestack final images

#2

Post by admin »

Hi Gottfried,

the same techniques will work for live stack - as long as the frames coming in are not saturated then the stack will not be saturated (although applying a strong stretch may push it to saturation even if it is not quite saturated in the underlying data). I would suggest to check an individual frame to make sure that only the brightest points in stars are hitting maximum pixel value (and not too many of those either).

cheers,

Robin
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