Orientation reported by Astrometry.net is not east of north

[Nicolas T]

Hi,

I believe there is an error in the orientation calculated by astrometry.net and that the angle reported is not East of north, contrary to what is indicated.

I found a previous conversation where this was discussed but it was inconclusive:

https://groups.google.com/g/astrometry/c/glVFictwNV4/m/wktcUMc_BgAJ

There is also this feature request about adding a North/East arrow to annotated images but it doesn’t really solve the issue in my opinion:

https://github.com/dstndstn/astrometry.net/issues/151

I understand that there are some complications with fit files, so I will use a jpg file (for which the orientation is not ambiguous) to demonstrate the problem.

Here is an exemple image of  such a jpg file (this image is not flipped)

https://1drv.ms/i/s!AgPwp5gOmTQUgfZzTKI7-PqgHg8Urw?e=RIPwoN

And here is the result of the astrometry.net solver on this image : https://nova.astrometry.net/user_images/9840187#original

In my view this is not correct and the 71,2 degrees angle reported is not east of north.

In this image, UP is 289 degrees east of north: see here: https://1drv.ms/i/s!AgPwp5gOmTQUgfcSzu-1bQIdyKRvOA?e=JqGIkq

cheers,

Nicolas

[Dustin Lang]

Yes, as discussed at great great length in that issue you linked to, there is a bug in the report, and it's surprisingly difficult to figure out the right thing in all cases.

I just removed the Orientation report on the web page - it's more trouble than it is worth.

cheers,

dustin

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[CaptAndy Sir]

Please don't remove the orientation.  I have found it  VERY helpful!

Thanks for all your efforts.

dw

[Dustin Lang]

Okay, compromise, I re-added the orientation value, but added the text:

"Orientation", may be incorrect, use at your own risk:

so enjoy.

cheers,

dustin

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