Enable phase_center inputs to be SkyCoord

[DanRyanIrish]

This PR enables the phase_center inputs to the Visibilities calculating functions to be given as a SkyCoord. The result is that the Visibilities object knows its phase center in a valid coordinate frame, and hence enable imaging routines to return Maps in the same coordinate frame.

[codecov]

Codecov Report

Attention: Patch coverage is 29.34783% with 65 lines in your changes missing coverage. Please review.

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Files with missing lines	Patch %	Lines
xrayvision/coordinates/frames.py	38.77%	30 Missing ⚠️
xrayvision/imaging.py	21.05%	15 Missing ⚠️
xrayvision/visibility.py	14.28%	12 Missing ⚠️
xrayvision/transform.py	20.00%	8 Missing ⚠️

Additional details and impacted files

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##             main      #77   +/-   ##
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  Coverage        ?   15.28%           
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  Files           ?        8           
  Lines           ?      968           
  Branches        ?        0           
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  Hits            ?      148           
  Misses          ?      820           
  Partials        ?        0           

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[DanRyanIrish]

Do not merge until #76 is merged.

[Copilot]

Copilot reviewed 10 out of 12 changed files in this pull request and generated 1 comment.

Files not reviewed (2)

• changelog/76.feature.rst: Language not supported
• changelog/77.feature.rst: Language not supported

Comments suppressed due to low confidence (2)

xrayvision/visibility.py:484

• Directly comparing SkyCoord objects with '!=' may lead to unexpected results due to floating point precision. Consider using SkyCoord's is_equivalent() method or a comparison based on separation.

if self.phase_center != other.phase_center:

xrayvision/transform.py:164

• [nitpick] The custom attributes 'Tx' and 'Ty' on the SkyCoord object are non-standard and could be confusing. Consider clarifying their purpose or using more conventional attribute names in documentation.

y = generate_xy(m, phase_center.Ty, pixel_size=pixel_size[0])  # type: ignore

[Copilot]

Indexing a SkyCoord object as if it were a sequence may result in an error since phase_center is expected to be a scalar SkyCoord. Use the existing attributes (e.g. phase_center.Tx and phase_center.Ty) instead of indexing.

Suggested change

	stix_vis.phase_center = SkyCoord(Tx=stix_vis.phase_center[1], Ty=stix_vis.phase_center[0], frame=Projective)
	stix_vis.phase_center = SkyCoord(Tx=stix_vis.phase_center.Tx, Ty=stix_vis.phase_center.Ty, frame=Projective)