Solving Spectrometer Problem: Angle of Prism & Min Deviation

[logearav]

Homework Statement

folks, while i do spectrometer experiment to find the angle of the prism and angle of minimum deviation, i encounter the following problems. please let me know how to overcome that
1) i first do the initial adjustment with telescope pointing towards the distant object so that i get a clear inverted image in the field of view
2) next, with the help of spirit level i make sure that my prism table in horizontal level
3) now i make the telescope in line with collimator and focus the sodium vapour monochromatic source and i get a thin, sharp slit exactly in the middle of the cross wire
4) now when i place the prism to find the angle of prism , i get the slit well below the field of view when i turn the telescope to catch the image of the source of light from both the reflecting faces.
5) with the help of the levelling screws at the bottom of the prism table i raise the image to the middle of the field of view
6) but when i proceed to find the angle of minimum deviation, once again the image goes below the field of view
why this problem occurs? please give me a solution... thanks in advance

Homework Equations

The Attempt at a Solution

 

[NateD]

It sounds like the issue is that the prism is not positioned correctly when you try to measure the angle of minimum deviation. When you set the prism in order to measure the angle of minimum deviation, it should be positioned with the hypotenuse of the prism facing the light source, and the base of the prism facing the telescope. You may also need to adjust the angle of the prism so that the refracted light is at the correct angle for your measurement. Finally, you should make sure that the prism is properly centered and level so that it does not move when you take the measurement.