Type initial (EPOCH1) and final (EPOCH2) epochs and coodinates a₁, d₁ for initial epoch only - in the one of forms) and press "SUBMIT" (if EPOCH2=EPOCH1, EPOCH2=EPOCH1+10). Press "CLEAR" before the next calculation. Sign "-" for the d in form (^o ' ", first line)  insert in the special field before the field of ^o. Sign can be inserted into the field for ^o, but in case of -1^o < d < 0^o in this field will be "0" and sign will be lost.