Hogben.- — Night Marching by the Stars. 



515 



be on the left or east of Markab. 

 named will be in the position just 

 10.30 p.m. respectively. (See note 3 

 B. Second Method. — The direction 

 by using Tables I and II below in 

 instance, supposing a night march is 

 and midnight on the 24th April, 

 we see that the stars nearly south du 

 afterwards Spica. Table I shows us 



On the 8th or 9th October the stars 

 referred to at about 7.30 p.m. and 

 (b) above). 



may be found somewhat more exactly 

 conjunction with the diagram. For 

 fixed to take place between 8.30 p.m. 

 From the diagram (star map No. 2) 

 ring that time are, first, Eegulus, and 

 that Eegulus on the 1st May will be 



10° 



fSouthern 



[horizon 



y vvvvvv vvvvvvvvvvvvvvvv 



Star Map No. 2 (looking South). (For latitude 50° N.) 



on the meridian about 7.30 p.m. ; therefore, on the 24th April (or seven 

 days earlier) it was on the meridian twenty-eight minutes later, say at 

 8 p.m. Similarly, Spica is on the meridian about 11.15 p.m. on the 24th 

 April. 



At 8.30 p.m., or thirty minutes after its meridian transit, Regulus (as 

 we see from Table II) is 12° west of south ; at 9 p.m., 23° west of south ; 

 at 10 p.m., 44° west, or nearly south-west; and so on. In other words, 

 each five minutes it alters its bearing towards the west by nearly 2°. 



At 8.30 p.m. Spica will have two hours and three-quarters to go before 

 its meridian transit, and its bearing will be about 43° or 44° east of south, 

 or nearly south-east ; at 9.15 it will be 32° east of south ; at 10.15, 17° east ; 

 and so on. In each quarter-hour it alters its bearing about 4°. 



