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The Mounting 2
There is too great a latitude in ideas and design in telescope mounts for the subject to be entered into here. Our primary objective is to enable the amateur to mount his telescope cheaply and
Fig. 69. Useful pipe fittings: A, tee; B, reducing tee; C, wye or lateral; D, 45° elbow; E, 45° street elbow; F, eccentric reducer coupling; G, offset coupling; H, reducer coupling; I, heavy flange; J, offset flange; K and L,close and short nipples.
efficiently. What will be described is a conventional form of mounting known as the German type, utilizing pipe fittings, which are admirably adaptable to the purpose. A study of the problems of the construction will be of aid to those fortunate amateurs who
Fig. 70. Pipe mount (first type). The axes turn on threads of the close or short nipples, L. Other parts can be identified from Fig. 69. The eccentric reducer F is used in an effort to bring the center of gravity over the pier. As this effects
only partial correction, the instrument's balance is improved by casting the pier base eccentrically in the concrete block.
are in a position to design and machine their own castings. The pipe fittings are obtainable in iron or brass at any steamfitters' or plumbers' supply house. Useful fittings are illustrated in Fig. 69. Shown in Fig. 70 is a fixed pipe mount in which the polar and declination axes turn on the threads of the short nipples L.
The fittings are of 3" pipe size, and can be identified from Fig. 69. The height of A above the ground should be such that the eyepiece is at a comfortable height when the tube is pointed to the zenith. For better bearing action, the threads of the polar
and declination axes should be lapped in.
To do this, paint the threads with a mixture of No. 400 carbo and cutting oil, and screw the tee, or flange, on and off repeatedly, grinding away until a few more threads become engaged. Then clean out all grit with a stiff brush and kerosene oil, screw the parts together again, and add lubricating oil. A much smoother turning action will be the result. No other
machining is required on this simplified mounting. The counter-weight may be of iron, lead, or concrete.
Next- The Mounting part3
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