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INDI Library v2.0.7 is Released (01 Apr 2024)

Bi-monthly release with minor bug fixes and improvements

Optimal Sub-Exposure Calculator help

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The filter documentation usually states bandwidht at the FWHM level
Last edit: 10 months 3 weeks ago by Vladimir.
10 months 3 weeks ago #93322

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Hi i try to create a new camera following your description.
but it's possible to copy the new file on the original folder.
it seems than i don't have the authorization for that.
how can i do ( i'm using ekos kstars on a raspberry PI4 with stellarmate)
regards
Last edit: 9 months 4 weeks ago by vera .
9 months 4 weeks ago #93748

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sorry
finally i found a solution to have the correct acces and create a new file for my camera
JP
9 months 4 weeks ago #93749

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Sorry, I have not tried Stellarmate, but there should be a "local" folder where KStars stores some user configuration data. It should be a user writeable folder, but this folder is likely flagged in the OS as hidden.

On a standard Linux installation this folder would be under the user home folder, and named .local/share/kstars. (This folder would contain sub-folders for logs, astrometry, etc.) If you can find this folder, then create a new sub-folder named "cameradata". Then create your new camera file in this folder.
9 months 4 weeks ago #93750

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Finally I changed the folder autorisation
And now it works as expected
Thanks
9 months 4 weeks ago #93751

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8 months 3 weeks ago #94379

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CRASH

I try to click on clock icon but Kstar crash ad it close.
6 months 2 weeks ago #96435

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I will try to help, but I will need more information.

Can you enable the logging, and attach the log output file?

Open Ekos, and click the Logs button. Set to Verbose and Output to File. In the Ekos section check the "Capture" box.
Then go through the process you followed that caused the crash. Log files should get written to your local KStars/logs folder.

Thanks
6 months 1 week ago #96505

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A follow-up:

When you bring up the EKos capture tab, what camera is appearing?

I was able to cause a crash when I used a profile that had a camera manufacturer selected (in this case ZWO), but I did not have the camera attached. In this case, the Indi control panel opened, but it had no tab for a camera. The Ekos Capture tab was available, but no camera was shown.

When the Exposure Calculator is launched it attempts to determine which camera is active so that it can try to find the proper read-noise data file. So the crash is likely happening because no camera data is available in EKos. I was also able to cause a crash in the Ekos capture screen by attempting to capture an image when there was no camera selected.
6 months 1 week ago #96506

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I just wanted to raise a warning for those of you who have created your own camera data files. I would recommend that you make a back up copy, or mark your camera files as read-only.

The reason being is that the updated version of the exposure calculator now has the ability to directly download camera files from the github repository. The intent of the change is to allow users to better manage what camera files appear in the exposure calculator camera selector drop-down. But downloaded camera files will be stored user s home .local/share/kstars/cameradata folder. This means that a download of a file from github would potentially overwrite an identically named file in that folder.
4 months 4 weeks ago #97391

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Reviving this old topic because I'm looking for volunteers to supply me with some additional test data.

Last Summer I worked on a tool to calculate read noise for a camera to be used as input data for the exposure calculator. My results were not matching expectations so I set that project aside. But a few weeks ago I had time to re-visit this project. I found that the problem was not caused by my implementation of the calculations, but was actually caused by poor quality flat images which are used as inputs to the process.

At this stage of development; this tool only reads the necessary fits input files and produces a table of data. I then move that table to a spreadsheet to produce graphs. The results I'm seeing in my tests cases match the camera documentation fairly well, but my tests are limited to data from just my three ZWO cameras. See attached examples from my analysis of my ZWO guide camera.

In an email exchange with Jasem, he suggested that I seek additional input files from folks on this forum. I'd be very interested to get files for cameras from other manufacturers, (and I'm particularly curious to see data from a CCD camera).

So, I'm looking for a few folks who are interested in this subject, and are willing provide me with some fits files from their cameras. This may be an iterative process, as I may need to adapt my process. If you are interested in helping please read on.

What my tool needs for CMOS cameras is a set of two bias images and two flat images for each gain/iso setting that is to be plotted. For a CCD camera there would only be a single set of images.

The interval on the gain/iso selections does not need to be constant. As you can see in the attached example data, I started with gain intervals of 20, but increased the interval to 50 when I was at higher gains (that I'm less interested in using). On my ASI-290MM, my initial tests showed the step in read noise between 60 and 80, so I captured additional sets to isolate that.

The flat images should be taken with the camera only, (not through a scope). Try to make flat exposures that are about 1 second or longer, otherwise the process may not produce accurate results.

(Just to be clear, the issue I experienced last Summer was caused by my using an LED panel as a light source which was too bright, even on it's dimmest setting. This caused the exposure times for the flat images to be extremely short. These short flat frames were excessively noisy, and had very subtle banding artifacts. I believe that banding was caused a flicker in the LED light source probably from the pulse width modulated dimming circuit. So I now use a thick stack of white paper to dim the light source)

I might also need the digital to analog conversion bits value for the camera. I have not yet learned how to compute this from fits data.

So, if you are interested in helping me by providing some test data, please let me know. (If my process works, we can use the read noise data to build a custom camera file for the exposure calculator).

Thanks
3 months 1 week ago #98222
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I'm happy to help here. I've had a number of cameras over the years and still have access to most of them, I have bias and flats for all of them. They are, chronologically:

SBIG ST2000XM (CCD)
QSI 583wsg (CCD)
FLI Kepler KL4040 (sCMOS)
Moravia C5A-100M (CMOS)

So this should provide some additions to the database.

Cheers,
Richard
3 months 1 week ago #98229

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