This paper is designed for
the variable star observer who uses a telescope in the aperture range of 3 to
10 inches. The assumptions shall be made that the observer's eyesight is normal
and that the instrument is of good optical quality and mounted in a stable
manner. furthermore, it shall be assumed that the observer has had some
experience in variable star observing and that his observing conditions are
sufficiently good to allow him to see fifth magnitude stars or fainter with the
unaided eye on clear, moonless nights.