278 A Balcony Observatory. 



A BALCONY OBSERVATORY. 



BY HENRY J. SLACK, P.G.S. 



Among the numerous readers of the Intellectual Observer 

 who desire to become familiar with the various interesting 

 celestial objects within the reach of small telescopes, many 

 must have experienced the inconvenience of either looking out 

 of a window, or carrying their instrument into a garden every 

 time an observation has to be made. Some will have the 

 means of constructing a regular observatory, and will no doubt 

 profit by the instruction conveyed in the papers of Mr. Bird 

 and the Rev. W. Berthon. A more numerous section will, 

 like myself, have to devise other arrangements, and it may 

 interest them to know what I have done. 



My best place for observation was on a level with one of 

 the windows of my drawing-room, in a situation commanding 

 a view extending from N.E. to S.W. The length of my own 

 garden, together with a road, and the gardens of neighbours 

 opposite, gave me a deeper space than is common so near 

 London, and the width of my look-out was still better, as being 

 less interrupted by buildings or trees. My object was to 

 utilize this situation for star-gazing purposes, without offending 

 the taste of the household gods by any unsightly erection. 

 My telescope — having a fine three-inch glass, by Steinheil, 

 upon Gauss's principle — required about seven feet to be mani- 

 pulated comfortably, when a dew cap was at one end and an 

 observer at the other. I therefore devised an observatory 

 seven feet square, opening from the drawing-room by French 

 windows, and glazed all round. Two iron columns and a light 

 iron girder, erected in the garden, support at one end two 

 slabs of stone three inches thick and a few inches wider than 

 the internal dimensions of the room. The other ends of the 

 stone slabs are carried into the brickwork of the house. 

 The two stones were deeply grooved where they joined in the 

 middle, and fastened firmly together by running in lead. Upon 

 these stones, woodwork was fixed nine inches high, on the top 

 of which are two grooves, one inner and one outer, with flat 

 iron rails* on which the sashes slide. 



The top framework of this balcony observatory was 

 made something like the headpiece of an Arabian bedstead. 

 It is supported by two strong uprights close to the wall, 

 and by the framework of two fixed sashes three feet six 

 inches wide. No advantage would have been gained by 

 making these sashes to open, as the telescope was placed 

 just in advance of them, so as to command all the lateral 



