290 Star-Following with Table Stands. 



STAB-FOLLOWING WITH TABLE STANDS. 



BY EEV. E. L. BERTHON, M.A. 



The November number of the Intellectual Observer con- 

 tained a description of a new stand for astronomical telescopes 

 likely to be acceptable to amateurs. The inventor wishes now 

 to publish the sequel to that arrangement, showing a simple 

 way by which the heavenly bodies may be conveniently fol- 

 lowed, either, 1st, by a single movement of the one hand, or, 

 2nd, by a means entirely automatic. By referring to No. xxii. 

 page 283, it will be observed that the movement in altitude 

 is effected by a long screw turned by a little winch'; and 

 that in azimuth by a horizontal movement of the whole stand 

 upon rollers. 



It will be remembered that a slab of smooth slate, which 

 may be had for three or four shillings, was recommended as 

 the flat surface on which this stand should work. The slab 

 should be about thirty inches long and eighteen inches wide, 

 and instead of being fixed it should be made to revolve where 

 required about a pivot. To accomplish the improved work- 

 ing of this stand, two pieces of wood cut this shape 

 are fixed, one at each end of the slab, by means of a 

 wedge. On the side of one of these pieces— that 

 on the right hand — is placed a little sheave of brass 

 working on a pin. Over this passes a piece of fine 

 whipcord having a weight of three or four pounds 

 upon it, and the other end made fast to the piece of 

 wood on the other end of the slab. The cord is thus 

 stretched across the slab in a state of tension. 



We must now recur to the stand. The annexed 

 woodcut represents, in real size, a section of the hinder part of 

 the board or base : a is part of the long screw inclining up- 

 wards. This screw is prolonged backwards, and between its 

 two bearings 6 and c it has a well-turned cone of boxwood, 

 and terminates in a square end to receive the winch or handle 

 <(. The bearings l> and c are prolonged upwards and support 

 another spindle now to be described: it is made square be- 

 tween the bearings, and upon it is a flat wheel or disc of brass 

 having its edge milled like that of a shilling, which is made to 

 slide up and down the square spindle so as to touch the 

 wooden eone at any desired part. On tho same spindle behind 

 Hie aftermost bearing is a brass sheave with several grooves of 

 different diameters, e. Then; is also one moro little sheave/ 

 working on a pin, round which and also round one of the 

 grooves of the sheave e f is passed an elastic band to maintain a 

 constant pressure between the cone and disc. Finally tho 



