I have played Omega Ruby to completion, including the Delta Episode. I caught Groudon and Rayquaza, but I couldn't catch Deoxys. I went to the Mossdeep Space Center later on, and I learned that Deoxys might still be within my grasp. One of the scientists there said that Deoxys was somewhere along Route 131 (just east of Pacifidlog Town), but that was as narrow of a line as they could draw for it.
I looked all along Route 131, but it wasn't there at all. Is there a specific tile that I need to be on, or a specific time I need to look for Deoxys? Or is he hiding somewhere in Sky Pillar, or something? Any help would be greatly appreciated!