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

Bi-monthly release with minor bug fixes and improvements

New Internal Solver for Mac, Windows, and Linux -- Testing/ Experiments needed

  • Posts: 185
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Rob,

I was just shocked at how hot the CPU got. I don't normally see that widget while platesolving as part of a session. Of course, heat builds up a bit more with multiple trials back to back than it would in normal service where the shortest time between solves would be the slew and settle time when slewing to target after solving.

I can look at the multiple options. I just wanted to get you the default results. I can take that on in another session (which I may do on the desktop with liquid cooling instead of the NUC).
3 years 10 months ago #52968

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Ok I implemented this along with a couple of other changes. If you are using the Linux version you can rebuild after a git pull. If you are using Windows or Mac, I will need to rebuild it in a new version release first
3 years 10 months ago #52978

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I added a check for the amount of RAM on the system before allowing it to proceed to use astrometry with the inParallel option. Please see if this can resolve this problem.
3 years 10 months ago #52980

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Rob,

I ran several additional targets, typically running all solvers through all options. The typical order would be default, downsample2, small sized stars, mid sized stars and big sized stars. The csv file is attached. Any missing options should be assumed to be failed solves (although there could be the odd missed option).

The last image was run through the solvers 5 times for the default options. The results indicate that the single runs should be reasonably representative of the time required.

These were run on my PixInsight desktop, Intel i7-9700K, 64 GB RAM, liquid cooled.

File Attachment:

File Name: Sexy_Solve..._CDT.zip
File Size:9 KB
Last edit: 3 years 10 months ago by Richard Beck.
3 years 10 months ago #53006
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Rob, you have done a fantastic job by making Astrometry.net working without external programs.

I briefly have played with the Windows executable. I noted that the solving time of the internal solver and ASTAP are very comparable. Furthermore it work very well for very ultra short exposures. As a last test I tried large offset in the header position. For that I changed the declination in the FITS header. There seems a maximum search field limit of 15 degrees in place. For a 15 degrees error in the header the internal solver takes about 22 seconds to solve. ASTAP will solve in 6 seconds. :) I would be nice to be able to test it for larger offsets/errors.

Two of my test files:
ufile.io/ow361q1p

Not so important, but I could not get the classic Astrometry.net working ("All sky plate solver" for MS Windows). The slash versus back slash is understandable but the .exe extension seems wrong:

Default settings:
C:/Users/h/AppData/Local/cygwin_ansvr/etc/astrometry/backend.cfg
C:/Users/h/AppData/Local/cygwin_ansvr/lib/astrometry/bin/solve-field.exe
C:/Users/h/AppData/Local/cygwin_ansvr/lib/astrometry/bin/wcsinfo.exe


p.s. I suggest you select a more neutral name for the application. Especially for users which share a computer.


Han
author of the ASTAP program
Last edit: 3 years 10 months ago by han.
3 years 10 months ago #53476

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One more question. Can the solve speed be influenced by the number of stars extracted? For ASTAP you can limit the maximum number of stars extracted. Normally it's default limited to 500. For star rich images reducing it has a dramatic effect on the solve speed but reduces the reliability.

Han
3 years 10 months ago #53477

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It definitely speeds things up, you can see that if you use the settings of the sextractor part, e.g., limit max and min area. This reduces the number of stars found, and makes things much faster. The question is how do you limit the number of stars? If you first detect all and then only take (e.g.) the N brightest, the work/time had already been wasted. Stopping after N might end in an uneven distribution. How do you do it in ASTAP?
3 years 10 months ago #53478

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In ASTAP the brightest detected stars are separated on SNR value. It builds a SNR histogram making an quick extracting of the specified amount of the brightest stars relative easy. It's also essential because it tries to build the smallest quads (I call it tetrahedrons) possible and the database and image quads should be identical. This will only be the case if for both the image and database the same amount of brightest stars are selected.

There is fundamental difference between Astrometry.net and ASTAP with respect to the index and database. The ASTAP database contains only the star positions and the unused magnitude. The star database is sorted on magnitude so extracting the 500 brightest star easy. The Astrometry.net indexes contains already build quads.

I experimented with the Sexysolver Library tester "Cut Bright" and "Sat. Limit" settings but quickly the solving fails. If I set "Cut bright" at 50%, it detects half amount of stars but solving fails. Is this selection working correctly? For proper separation an accurate star flux measurement is required.


Note that for developing and debugging ASTAP the image viewer was essential. It allows in debug mode to plot the extracted stars and database stars.

Han
Last edit: 3 years 10 months ago by han.
3 years 10 months ago #53479

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Using the Sextractor, I can see the star are marked with red circles. Aha, so I have to select Cut Dim. Yes that makes a great speed difference.

Would a selection on a number of stars rather then % not be more efficient? For short exposures you don't want to throw away stars but for star rich images you want. So I would like to set a limiting number of stars.

With the setting CutDim=85% equals 500 stars of the original 3600, the solving speed is three times faster for large offsets.

Han
Last edit: 3 years 10 months ago by han.
3 years 10 months ago #53480

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There should be an option to filter out hot pixels. By a minimum HFD expressed in either in pixels or arcseconds. Here two two test files:

ufile.io/toia92ls


Han
3 years 10 months ago #53482

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Hi Han,

Thank you very much Han for testing the program out! So there are several goals of my little project. One of them is to support ASTAP as an option, so maybe you can help me with an issue or two with that one! Basically, this program will provide a universal Solving interface for all platforms in QT.

Very shortly, I should have a new version for you to test, I have done a lot in the last week and made some significant improvements, including in the ASTAP interface.

The backslashes and forward slashes actually do not matter when using QT on Windows. In fact originally, I had it entering backslashes on Windows, but in the end, it ended up being much more reliable to just use forward slashes. The internal libraries that QT calls upon correct the backslash/forward slash differences and accept either as input. The backslashes, though, caused problems when calling the ANSVR astrometry.net. So if you would like, I could have it display the backslashes to the user to make things more familiar, but internally in the program, forward slashes across the board worked much better.

The default paths worked perfectly for the ANSVR installation on my testing computer. Is ANSVR installed properly on the system or do you have a different path to the programs? I thought it was pretty universal from what I saw. What error messages does ANSVR print out when you try to solve using the "Classic Method". Also, I should not that it isn't so "classic" on windows since this method of accessing ANSVR was not available before I wrote this interface in my program. If the INT SEP EXT SOLVER method works and the classic method does not, I think that would point to it being an issue with python or netpbm.

In terms of the solving in ASTAP vs. astrometry.net, vs the internal astrometry.net etc. Yes ASTAP is a pretty fast option, but doesn't always solve everything the other ones do from what I have seen. Astrometry.net is very sensitive to the settings that you put into it. If we can perfect the sextractor settings and astrometry.net settings, I think it could be fast like ASTAP. On my Mac, it is faster than ASTAP right now. On my Windows Testing machine, I think ASTAP is a little faster. But maybe also we could improve the ASTAP solving in the program by using more of the options. In my new version, I added more of them. It should be out this weekend.

Really my goal is to make all of them better, optimized and easy to use in a program with an interface, so anything you can do to help make it better, I appreciate.

So the name is the sexiest one I could come up with combining things like Sextractor, Solver, and Astrometry. Ultimately, the name of the library won't be displayed prominently on a user's computer since it will be internal to programs like KStars, so I don't think that will be a problem. But if I come up with a better name, I can certainly change it. It's a much better name than SextractorSolver or SESolver.

Thanks,

Rob
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3 years 10 months ago #53487

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Yep, you are absolutely right. So my primary goal in posting on here and having lots of people test, is to hopefully get people to let me know what settings work best for different situations, so that I can make some selectable Sextracting and Solving options profiles. I want the default options to be good all around, but the different options profiles to be better at sextracting or solving different kinds of images or for different purposes.

For example, you could have an options profile that is specifically tuned to solve images that have a lot of nebulosity in them, so the solver would do more adjustments for that and try to solve for just the stars and not detect the nebula. Or you could have a profile that is tuned to solve images that have much more elongated stars, so if you have astigmatism or tracking problems on your mount, it would detect those as the stars. Or maybe there is a profile to specifically try to detect galaxies to get their positions and magnitudes.

In the new version I am planning to release shortly, it can calculate the exact position and magnitude of all the objects in the image and display all that in the table.

Thanks,

Rob
3 years 10 months ago #53489

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