tweak iteration

[Lylon SV]

Hello,

We’re trying to understand how we can solve the WCS with a certain tweak order and iterate to a higher order. While it seems like there is code that can do this, we’re not sure how to access it from the command line, or what parameters to use.  How can we control this process within the code, e.g. can we set the maximum number of iterations and the range of orders to try? The issue we’re having is that we’re currently solving with a tweak order of 3, however, systematic offsets remain between our sources and known sources throughout the field, and also at the corners of our field images (which is less surprising). We believe that iterating from a lower order to a higher order might be able to improve  the plate solution over most of the field.  Unfortunately, starting with a higher tweak order often produces a solution that has other issues and large offsets.  The current command that we’re using looks like this:

command = f”solve-field  --no-verify --no-plots --overwrite --uniformize 20  --sort-column {‘flux’} \
        --tweak-order \“{3}\” --ra \“{center_ra}\” --dec \“{center_dec}\” --radius \“{20}\” \
            --out \“{new_fits_name}\” --dir \“{write_dir}\” --temp-dir \“{temp_dir}\” \
                --new-fits \“{new_fits_path}\”  -X \“{x}\” -Y \“{y}\” -w \“{image_width}\” -e \“{image_height}\” \
                \“{xyls_file}\“”

Please let me know if you need more information on my end.

Thank you very much for your help!

[Dustin Lang]

Internally, the solve-field program does iterate up to the desired tweak order.

If you want to send an example image, that might be helpful for us to understand what might be happening.

cheers,

dustin

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