I run "tweakreg" on WFC3/UVIS images which were observed in a single day with 4 orbits. Everytime I run "tweakreg", I don't have the two-dimensional histogram of offsets while the other two plots - vector plot and residual plot - come out without any problem.
Anyone knows why?
For your reference, I set both "use2dhist" and "see2dhist" parameters as "yes".
I run PyRAF in AstroConda environment on my iMac OS 10.13.5 (High Sierra).