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

Bi-monthly release with minor bug fixes and improvements

ASI Camera - Gain/Offset/x-Bit

This won't work, what if a camera has ISO + Gain + Offset ...etc? At any rate, I implemented a solution, I removed Gain setting and replaced it with a new setting: Custom Properties. So using Custom Properties, you can set any number of properties in the sequence from the list of available numeric properties, but you have to set it first in INDI Control Panel, then "record" it in the sequence then proceed as normal. It should be in v2.8.1 due some time next week.
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6 years 7 months ago #18422

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When I try to adjust Gain or Brighness (=Offset) with the slider or the spinner it moves in quite large increments. I'm guessing they both move in steps of 10% of the range. I tried to manually enter a value in the input field but it would not edit. Can the spinner be made to move in single units or allow manual editing?
6 years 7 months ago #18584

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You can edit all of them directly.
6 years 7 months ago #18587

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So if I am understanding correctly. I set the gain, offset, etc... in the Indi control panel, then choose "controls" in the Custom Properties. Now when I add an entry to my sequence it will use the gain, offset, etc... settings I set in the Indi control panel.
6 years 7 months ago #18633

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Exactly
6 years 7 months ago #18635

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And if I want to correct a wrong setting on a job is this the right procedure?:
Double click the job to go into edit mode
Enter correct settings in Control Panel
Click Custom Properties
Click Apply (since the control group is already selected)

By the way, for ASI owners, the Offest is labelled Brightness
Also, my earlier issue is resolved and I can edit the numbers. I suspect it was something to do with not having 12V power to the camera. The camera works without 12V but appears to be less stable.
As another related question (still learning all the features in Ekos): I want to set up a sequence of LLRGB that repeats with different gain/offset for L vs RGB. So I set up the sequence with 4 items (with L having a count of 2). So I guess I then set up the Scheduler to run the whole sequence, say, 50 times?
6 years 7 months ago #18640

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Last night I tried out the ASI071 for first time, with 80-500 Apo. Not sure if the issue I experienced is a bug or a matter of poor parameter setting:

If I chose the default settings (controls), with gain = 0 and brightness = 8, I only get a fits-picture with stars being visible if exposure is greater then 30 sec. If I set exposure to e.g. 29 seconds, I only get a fits picture that is essentially black (not a hint of any star). Same happens if I increase the gain to 20, and brightness =48, I get a picture with visible if exposure is at minimum 4.3 sec, if I reduce the exposure to 4.2 or change the brightness to 40, I get a black picture. I.e. there is not an incremental change of the picture. Somehow looks like there is a sort of threshold, below which the picture becomes "black".

Btw: If I set the parameters for the AIS071 for long exposure, how can I do the auto-focusing - would assume for auto-focusing, with e.g. 0.5 sec exposure, I would chose different parameters?

Update: After analysing the pictures in FITSWORK, I realize that also the "black" picture has all the information, after stretching the histogram, stars became visible. Could it be the case that I need to uncheck the flag for autostretching in the FITS settings in EKOS?

Many thanks in advance for any support!

Helge
Last edit: 6 years 7 months ago by Helge.
6 years 7 months ago #18646

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Quick update, seems like my first pictures suffered from far too low gain/offset for the short exposure times that I was running. So clearly no bug, but the user...

Looking at the histogram (or statistics) as provided by the Fits viewer, I wonder if there is an expected range of frequency/intensity, if the gain and offset settings are within a reasonable range, for short and long exposure times?

One more question, if I was setting the gain and offset in the Control Panel for longer exposures, do. I need to change those parameters if I wanted to run the autofocuser?
6 years 7 months ago #18710

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The focus module require stars not to be saturated, so as long as that is met then no issues.
6 years 7 months ago #18719

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What I would personally suggest is to use the recommended Unity settings 139/50/21for exposures between 120-240sec. Unity settings are considered a balance between SNR and Resolution.

When you're happy with the camera you can then try the optimal SNR settings which are 70/50/10 for 480-600secs.

Don't forget, you will need Bias, Darks and Flats at the same camera settings.

For focusing between filters you'll probably need to find a setting that allows focusing to be done quickly; 300/50/21 will get you to a few seconds exposure. Trial and error here is essential.
Skywatcher 190MN - EQ6 Pro (with Belt Mod) - ASI1600MM-Cooled - ASI EFW7 - ASI120MM - WO f4 Guide Scope - Rigel nStep - KStars/Ekos - KDE - PixInsight
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6 years 7 months ago #18727

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Thanks a lot for the proposed setting, will give it a try on next occasion!

One big issue is remaining, after some "research" on the internet, looks like I have a fair bit of amp-glowing with the ASI071 in combination with the Raspberry USB2 interface. Adjusting the bandwitdth (increasing to 100) seems to have a slightly reducing effect, but still it remains clearly visible (see attached example, with 1 and 8 seconds exposure (if I recall correctly, I set the offset at roughly 10% of the gain - could not find an entry in the FITS Header to doublecheck). The bandwitdth was left here at 40.

Is there any advice out there on this issue?

Update: Found on astrolumina homepage some advice on reduction of amp glow by lowering the USB traffic to a minimum of e.g. 1 - could the same approach be applied to the ASI071? I was trying in the indi controls to reduce the bandwidth below 40 - but that was not possible (not sure of this is actually the same parameter).
Last edit: 6 years 7 months ago by Helge.
6 years 7 months ago #18738
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Replied by Jim on topic ASI Camera - Gain/Offset/x-Bit

I have been collecting some information along the way for various ASI cameras as I don't have easy access to the settings in the ASCOM driver. Here are a couple settings the ZWO recommends for the ASI071 (ASCOM presets)

ASI071

Gain 50, Offset 12
- Dynamic range = 13.1 stops
- True gain = 1.5 e-/ADU

Gain 90, Offset 20 (Unity Gain)
- Dynamic range = 12.5 stops
- True gain = 1 e-/ADU

Gain 150, Offset 35
- Dynamic range = 11.8
- True gain = .5e-/ADU
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6 years 7 months ago #18739

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