In newtons ring experiment we place the lens setup below a microscope which is then moved vertically until the fringes can be seen.
In case of Determination of Cauchy's constants, we use a spectrometer. The spectrometer consists of a collimator which is mounted on the rigid arm and a telescope mounted on the rotation table arm which can rotate in a horizontal plane about the axis of the instrument. A prism table of adjustable height is mounted along the axis of rotation of the telescope.
Is there any problem if we use a telescope to view newton's rings?