Hi,

I am updating the french manual of Ekos. So I am going to test the Alignment module in simulation mode: Telescope simulator, CCD simulator, Guiding simulator. GSC is loaded.
I setup expo=5, gain=100, bin=2x2 and with the different methods, StellarSolver, astrometry.net local, ASTAP local, the plate solve is unsuccessful in all case
I try to Load & Slew an image of M33, no problem.
Would you have an explanation please ? Hereunder, the message of Ekos with StellarSolver.

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2021-04-25T14:01:53 Solver Failed.
2021-04-25T14:01:53 Solver was aborted, timed out, or failed, so no solution was found
2021-04-25T14:01:52 Starting Internal StellarSolver Astrometry.net based Engine with the 4-SmallScaleSolving profile. . .
2021-04-25T14:01:52 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2021-04-25T14:01:52 Image width: 2772 pixels, Downsampled Image width: 1386 pixels; arcsec per pixel range: 1.09784 to 2.6961
2021-04-25T14:01:52 Scale range: 25.36 to 62.28 arcmin wide
2021-04-25T14:01:51 Configuring StellarSolver
2021-04-25T14:01:51 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2021-04-25T14:01:51 Stars Found after Filtering: 6
2021-04-25T14:01:51 Keeping just the 50 brightest stars
2021-04-25T14:01:51 Removing the stars with a/b ratios greater than 1.5
2021-04-25T14:01:51 Stars Found before Filtering: 6
2021-04-25T14:01:51 Starting Internal StellarSolver Sextractor with the 4-SmallScaleSolving profile . . .
2021-04-25T14:01:51 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2021-04-25T14:01:51 Disabling the inParallel option.
2021-04-25T14:01:51 Not enough RAM is available on this system for loading the index files you have in parallel
2021-04-25T14:01:51 Evaluating Installed RAM for inParallel Option. Total Size of Index files: 31.7906 GB, Installed RAM: 7.71627 GB, Free RAM: 0.561001 GB
2021-04-25T14:01:51 Automatically downsampling the image by 2
2021-04-25T14:01:51 Image capturée.
2021-04-25T14:01:48 Capture d'une image...
2021-04-25T14:00:32 World Coordinate System (WCS) is enabled. CCD rotation must be set either manually in the CCD driver or by solving an image before proceeding to capture any further images, otherwise the WCS information may be invalid.
2021-04-25T14:00:32 Inactif.

Thank you for your work on the documentation. Two tips:

1. Set gain to 100
2. Change telescope focal length so that the FOV is at least 60x60 arcminutes. This would make it solve much quicker.

I make the plate-solving and PA on my laptop and all is OK. So I have an issue on my desktop.

I remove GSC and GSC-DATA in order to re install it, but unfortunately I deleted it from the Synaptic Database. And It seems they are no longer available in the database. So impossible to install manually. Have you information about that please ?

I purge the installation of the GSC files and make a new install, but no GSC and GSC-DATA ! Have you a solution please ?

Hi Jasem,

I find out your site with the GSC files. It's OK. But I have always issue with plate solving on my desktop. Hereunder messages obtained with Local Astrometry.net .

2021-04-26T15:57:52 Solver Failed.
2021-04-26T15:57:52 There is no sextractor at /usr/bin/sextractor, Aborting
2021-04-26T15:57:52 Automatically downsampling the image by 2
2021-04-26T15:57:52 Image capturée.
2021-04-26T15:57:48 Capture d'une image...

With Internal Solver:

2021-04-26T16:01:15 Solver Failed.
2021-04-26T16:01:15 No stars were found, so the image cannot be solved
2021-04-26T16:01:15 Starting Internal StellarSolver Sextractor with the 4-SmallScaleSolving profile . . .
2021-04-26T16:01:15 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2021-04-26T16:01:15 Automatically downsampling the image by 2
2021-04-26T16:01:15 StellarSolver only uses the Internal SEP Sextractor since it doesn't save files to disk. Changing to Internal Sextractor.
2021-04-26T16:01:15 Image capturée.
2021-04-26T16:01:11 Capture d'une image...

Success with Astap ! Champagne ! Why ? Mystery !

Why into the Alignment tab, Solver Mode displays always StellarSolver regardless of the chosen method ?

It says it right in the log "There is no sextractor". So install it

sudo apt-get -y install source-extractor

Thank Jasem. Yes I had noted it and I checked the presence of sextractor only. But source-extractor was already installed, v2.25.0+ds-2.

I check all the Options of Alignment tab between my desktop and my laptop to be identical.

In order to update along the time the french Ekos manual, it is easy for me to have on the desktop the wordprocessor and Kstars. So I can take screen copy for the document and more. Thank for your help.

PS: I change the parameter Sextractor Binary from /usr/bin/sextractor to /usr/bin/source-extractor and the plate solve runs at last ! OK for Astrometry.net and Astap Local.

PS2: The Internal Solver doesn't run.2021-04-26T20:24:45 Solver Failed.2021-04-26T20:24:45 No stars were found, so the image cannot be solved2021-04-26T20:24:44 Starting Internal StellarSolver Sextractor with the 4-SmallScaleSolving profile . . .2021-04-26T20:24:44 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++2021-04-26T20:24:44 Automatically downsampling the image by 22021-04-26T20:24:44 StellarSolver only uses the Internal SEP Sextractor since it doesn't save files to disk. Changing to Internal Sextractor.2021-04-26T20:24:44 Image capturée.

At least I find out the reason of the issue. Values for the SmallScalingSolving were wrong and so stars were not detected.