knro wrote: Thank you for the detail investigation. This indeed appears to be a bug but I didn't have enough time to investigate it. Maybe you can spot the issue here ? This is where it's calculating the center points for each mosaic panel.
knro wrote: RA is in hours, but yeah it's more likely to do with spherical trig. The calculation in Mosaic assumes a flat plane which is only approximate for very small angles and breaks down over large areas. Will have to look at it more in the future unless someone wants to step it to fix that.