This has been adapted from the USINT dither page here.

For Cycle 24 observations and onwards, ACIS dither parameters have been doubled by default. These are summarized in the table below.

  
      
Summary of Cycle 24 defaults
----------------------------
Det   Rows   Amp["]  Period[s]      Amp[deg]        Freq [deg/s]     Freq ["/s]
             Y * Z    Y  Z         Y       Z           Y       Z       Y      Z
ACIS-I >128  16*16  1414 2000.0  0.004444 0.004444   0.2546 0.18     916.56 648.0
ACIS-S >128  16*16  1414 2000.0  0.004444 0.004444   0.2546 0.18     916.56 648.0
ACIS-I<=128   8*16  707  2000.0  0.002222 0.004444   0.5091 0.18    1832.76 648.0
ACIS-S<=128  16* 8  1414 1000.0  0.004444 0.002222   0.2546 0.36     916.56 1296.0