I shot some footage last week for the express purpose of creating a Hi-Res mosaic. It consist of four prime focus shots of the disc and proms.
All shots are the same configuration and settings and number of frames.
All were completed within 10 to 12 minutes. Number of frames about 2000 each and 250 best stacked in Registax6 and flats applied. Prom were done the same way after the disc. I have tried to blend the images with and without the proms.
The problem is Photoshop CS6 merges all four images but separates the top and bottom. For some reason it joins the two haves ok but puts the top on the bottom and bottom on top as two separate images. Tried joining from north to south and it kicks out the NE quarter. Here is the NE quarter in B/W and colour and the two halves as PS produces them.
Any ideas

PS Have already thought of the garbage bin