the adjustable stop 26 can be used to set a rightmost position 28 for travel of the top piece 22 the display 18 can then be set to read zero when the top piece 22 is in the rightmost position 28 and the display 18 will display a relative measurement or displacement when the top piece 22 is moved away from the rightmost position 28 0030 fig6 presents another embodiment of a stage 10 according to the present invention the stage 10 here is a rotary stage 32 that is equipped with a digital scale 34 a detector 36 and a display 38 which is connected with the detector 36 by a signal wire 40 this rotary stage 32 can also be defined as having a top piece 42 and a bottom piece 44 with the top piece 42 including the digital scale 34 and the bottom piece 44 including the detector 36 and the display 38 in use the top piece 42 of the rotary stage 32 here can be turned clockwise or counter clockwise and in this embodiment the top piece 42 can even be revolved completely many times in either direction this moves the digital scale 34 relative to the detector 36 causing the detector 36 to send a signal to the display 38 via the signal wire 40 of course the top piece 42 can also be held fixed and the bottom piece 44 be rotated or both pieces 42 44 can be rotated the detector 36 and the display 38 here can be the.