/TURRET sets the position of the turret on which the dichroic reflexer is mounted. This action directs the infrared beam from the telescope to the dewar to be used. The turret can be positioned in any one of four positions identified by the keywords A_POS (or 1), B_POS (or 2), C_POS (or 3), and IMB_POS (or 4). Dewars can only be mounted on the IMB ports corresponding to position keywords A_POS (or 1) and C_POS (or 3). CASPIR is mounted on IMB port position A. An IMB/TURRET=A_POS command is implicitly executed when a CASPIR command is first issued.