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Resolving M20 with astrometry.net fails

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Hi all,
I have a very strange problem using astrometry.net. When I am pointing to M20, the plate solver cannot find a match. As soon as I slew on a different location - even slightly different - everything is fine.

My current solution: I use the online plate solving for M20 and the local one for everything else.

Any idea?

- Wolfgang
4 years 7 months ago #41890

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I'd say it happens. More and more often I use a different, "easier", field of view than the object I want to capture. For example, when capturing NGC6888, I may run the plate solver and the focuser on the Sadr area only. That field allows faster preliminary operation before shifting to the actual target. In my specific case, it helps when I capture in Ha without motorized filter wheel, although the scheduler script is slightly more complex.

-Eric
4 years 7 months ago #41949

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Probably depends on the FOV. I had it fail on M13 when I tried solving the full field without using the field flattener. Center subfield worked.
With my setup of astrometry.net (0.78) it does solve M20, even the non-flat version. My (full) FOV is 130x100 arcmin.
4 years 7 months ago #41950

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Hello! I've just arrived here after using Sequence Generator Pro for most of the last year.

For what it's worth, SGP has a known issue plate solving M20 as well, it's been reported on their forums too. Very weird, it's not like it's one of these crazy-osbscure DSOs...
The following user(s) said Thank You: Eric
4 years 7 months ago #41991

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Had tried it again yesterday, with a 'live solve' case. Pointed to M 20 in KStars and then had EKOS solve:
[2019-08-12T22:11:13.702 WEST INFO ][     org.kde.kstars.ekos.align] - "Capturing image..."
[2019-08-12T22:11:17.819 WEST INFO ][           org.kde.kstars.fits] - Loading FITS file  "/tmp/fitsLYuMwD.fits"
[2019-08-12T22:11:17.830 WEST INFO ][     org.kde.kstars.ekos.align] - "Image received."
[2019-08-12T22:11:17.839 WEST INFO ][     org.kde.kstars.ekos.align] - "Starting solver..."
[2019-08-12T22:11:19.623 WEST INFO ][     org.kde.kstars.ekos.align] - "Solver completed in 2 seconds."
[2019-08-12T22:11:19.629 WEST INFO ][     org.kde.kstars.ekos.align] - "Solution coordinates: RA (18h 04m 04s) DEC (-22° 59' 47\") Telescope Coordinates: RA (18h 03m 51s) DEC (-22° 58' 14\")"
[2019-08-12T22:11:19.633 WEST INFO ][     org.kde.kstars.ekos.align] - "Syncing to RA (18h 04m 04s) DEC (-22° 59' 47\")"
[2019-08-12T22:11:19.813 WEST INFO ][     org.kde.kstars.ekos.align] - "Mount is synced to solution coordinates. Astrometric solver is successful."
4 years 7 months ago #41994

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I did a test with the Tycho2 catalog instead of the 2Mass catalog and got a resolution after 2 secs on my MacBook, while the 2Mass catalog took more than 70 secs. I did not check it on my Raspberry, but maybe that is the solution to this case.

Which catalogs do you use for astrometry.net?

- Wolfgang
4 years 7 months ago #42083

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