276 H. C. RUSSELL. 



All the star clusters which one could see under favourable- 

 circumstances with a three inch telescope have been put in, — 

 for the selection of these our own photographs were very useful — 

 all are distinctly marked by the letter in a circle. It is hoped 

 that the ease with which these may be found will be a conveni- 

 ence to many. The star positions have been computed and plotted 

 for the epoch 1900, so that the chart will be available for some 

 years without serious errors from precession. 



The intention is to have the chart printed on thin or translucent 

 paper, which may be placed on a circular piece of glass or other 

 translucent material, so that it can readily be turned round in a 

 holder in accordance with the instructions on its margin, when 

 it is desired to get the stars on it into the positions then occupied 

 by the stars in the heavens. This method of mounting is not 

 new, but has been too much neglected, and I have adopted it 

 because I think it will be a most important aid to the beginner, 

 who as a rule gets very much confused by having to look at a 

 star chart bound up in a book and placed the wrong way, and 

 then mentally turn it round into the position in which he sees the 

 stars in the heavens. In use it will be found exceedingly con- 

 venient to have some sort of frame or box which the star chart 

 can be placed upon close to a lamp, and if much use is to be made 

 of it there is a decided advantage in having a box which will hold 

 the lamp and the chart in the most convenient position. It is an 

 advantage to have the chart neither vertical nor horizontal, but 

 in a position midway between these two, so that when one is in 

 the ordinary position for reading, the chart is at right angles to 

 the line of sight, and therefore in the most convenient position to 

 use. Provision should also be made for turning the star chart 

 round and settting it in any desired position. 



The original drawing measures thirty inches in diameter, and 

 the greatest care has been taken in plotting the stars in their 

 exact positions, and in making every detail as clear and sharply 

 defined as possible, and the lettering is on such a scale that every- 

 thing can be read, even when the chart is photographically reduced 



