GWCS for Magellanic Stream

[zheshishuoshuo]

"Hello, I am a newcomer to GWCS, and I am currently trying to create a world coordinate system for the Magellanic Stream using GWCS, and I hope to reproject data from other coordinate systems into this coordinate system, but it seems quite challenging. I have looked through the GWCS documentation, but there don't seem to be any complex examples. The SkyCoordinate for the Magellanic Stream is defined in gala.coordinates.magellanic_stream and is described at Tools. Can you provide some examples and advice?

[nden]

Hi @zheshishuoshuo, are you aiming to define a coordinate frame, i.e. an object similar to the frames in astropy.coordinates? If so you need to look at the astropy.coordinates package and see how to add a new frame. This will allow conversion between coordinates in different frames.

OTH, if you are aiming to define the transforms from a specific instrument/detector to a specific coordinate frame as defined by astropy.coordinates, then gwcs is the tool for this. This is usually done to tie observations from a specific instrument to a standard coordinate frame.
Could you clarify what the goal is?

[zheshishuoshuo]

Here's the situation: I'm looking to reproject data from standard coordinate systems such as ICRS and Galactic coordinates into non-standard coordinate systems like Magellanic coordinates, Sagittarius Stream coordinates, and Complex A coordinates. However, I've encountered difficulties using the WCS within astropy to achieve this transformation for the latter coordinate systems. Consequently, I've turned to GWCS for assistance. I'm still struggling to grasp how to implement these more complex world coordinate systems, and I haven't been able to find any examples to guide me. May you give me some advice?