Newbie here just trying to learn Siril so apologies if I’m missing something basic. I’m running Siril 1.44 on a Silicon Mac running Tahoe.
I opened a .fit file of M31 and went to Plate Solver. I didn’t realise that I didn’t need to search for M31 in the image parameters as it had already got the ascension and declination co-ordinates from the file so I searched for M31 and it entered it in the window below where it says Resolver and Name. Everything was fine for that image.
Later I opened a .fit file of Rosetta and went to Plate Solver. It still was showing the co-ordinates for M31 as if it wasn’t reading the metadata. I clicked on Get Metadata from image and it corrected the co-ordinates but it still said M31 where it says Resolver and Name. When I tried to apply it, console said “Plate Solving failed. The image could not be aligned with the reference stars.”
I then searched for ngc2244 and that updated the Resolver and Name section so that it no longer said M31 and now said NGC2239. but the co-ordinates didn’t change as they were still correct from loading the metadata from the image. When I then clicked on Apply, it completed successfully.
So, even if the co-ordinates are correct, if the Resolver/Name bit is set to something else, it won’t work but there doesn’t seem to be a way of deleting it and so you always have to search which seems to defeat the point of the metadata.
Am I missing something, is there an easy way to delete a previous search so that it just loads the metadata correctly?
You’re not missing anything fundamental here, but there are two separate things involved in the Plate Solver dialog.
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The image coordinates come from the metadata.
When you load an image, Siril automatically reads the RA/Dec coordinates from the FITS metadata and updates the coordinates in the Plate Solver. There is no need to click “Get Metadata from image” for this.
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The “Resolver / Name” field is a separate search field.
The object name shown there is not taken from the FITS metadata and is not automatically updated when the coordinates change. It simply contains the object from the previous search. In your example, it remained set to M31 after you opened the Rosetta image.
So when you opened the Rosetta image, Siril had already correctly updated the coordinates to those of Rosetta, while the Name field still displayed M31. These are independent inputs.
The important point is that the object name is only a search aid; it is not part of the image’s coordinate metadata. Therefore, you don’t need to search for the object again just because the Name field still displays the previous search.
I would recommend having a look at the Plate Solver documentation for more details on how these fields are used.
So the metadata is doing its job: the coordinates are automatically updated when the image is loaded. The previous object name remaining in the search field does not mean that Siril is using M31’s coordinates.
Cheers, for that I understand that better now. Thank you. However, I’m still confused by the fact that whilst the RA/Dec coordinates where read from the FITS metadata why would Plate Solver fail when Resolver / Name was showing M31? The only way I could get it to work was by searching for ngc2244 as well. If I could have deleted the M31 from this field, it feels like Plate Solver would have then worked (I may be wrong). I just don’t understand why it would fail when the coordinates are correct but the Resolver/Name are for something else if they are truly independent? If it is the case that you can’t have coordinates set for one thing and Resolver / Name showing something else, then surely you should have the option to remove whatever is listed rather than having to always replace it when the data is already in the metadata???
I’m sure not; it wouldn’t have made any difference. The algorithm doesn’t look at that field, which is just for getting the coordinates from the object. The reason is that the coordinates must be slightly different in the two cases.