In HKL manual we found a notation that 2Θ could go into cassette rotx. However, this doesn't seem to work. According to the R-axis, we have set 2Θ to -10 degrees. Does the 2Θ option work correctly?
The 2Θ swing is described by cassette rotx in Denzo, with the opposite sign to the R-axis definition for 2Θ. distance is defined in Denzo as the distance between crystal and a point there beam intersects detector; it is = R-axis distance / cos(2Θ). x beam and y beam are the actual position of the beam on the detector during exposure at the current 2Θ (not at 2Θ =0). x beam and y beam change with 2Θ, mostly y beam. If the detector is aligned perfectly x beam does not change. The y beam, in extreme cases, may be outside the detector. The correct value may be negative or more than 200 in such case. The definition in Denzo is that the cassette (detector) center of rotation is the point where the beam intersects detector surface. R-axis (2Θ) rotation definition makes the crystal at the center of detector rotations. All options in Denzo, including autoindexing, work with any detector orientation. Only the resolution display in XdisplayF is incorrect for detector with 2Θ non-zero.
Since version 1.96.0 the 2Θ value can be set by simple keyword cassette twotheta. In case of that command there is no need to enter re-calculated distance and x beam y beam values. These values should be the same as values entered for 2Θ =0. Also during the processing XdisplayF shows correct resolution.