Hi all,

I am creating an application in which I need to display HMI magnetograms in CEA projections. Because Matplotlib is not an option for this project, I need to plot everything manually with a different package.

To be able to graph these images, I need to label the ticks on the axes, but I’m having trouble finding the correct tick locations. I need pixel coordinates to graph ticks, but I want ticks separated at intervals based on the world coordinates. For example, if I needed a tick at a latitude of 30 degrees, I can’t just convert any arbitrary coordinate along the 30 degree latitude line to pixel coordinates, because the line is curved in the image. So I need to be able to find the specific pixel coordinates of a point whose latitude is at 30 degrees but also at the 0 pixel x coordinate. Basically, I’d like to be able to find the coordinates of a point using two different coordinate systems for x and y.

I know it is possible to calculate these manually, but as I am using Astropy wcs for everything else coordinate-related, it would be nice to keep everything consistent. Is there any way to do this?

Thanks in advance