618 Tables 788 and 789 



TABLE 788. — Values of Log (no. stars)/(sq. degree) Brighter Then Photographic 

 Magnitude, m. at Stated Galactic Latitudes 



Taken from Publ. Groningen, van Rhijn, 1929, which see for far more detailed values 

 for both latitude and longitude. An excess of stars, especially S. of 0° latitude, between 

 longitudes 240 and 6o°, and a deficit elsewhere (Sears, Mt. Wilson Contributions, 301, 

 346, 347, also Publ. Astron. Soc. Pacific, 40, 303, 1928). 



TABLE 789.— Numbers and Equivalent Light of the Stars 



The total of starlight is a sensible but very small amount. This table by Chapman, shows 

 that up to the 20th magnitude the total light emitted is equivalent to 687 ist-magnitude 

 stars, equal to about the hundredth part of full moonlight. If all the remaining stars are 

 included, following the formula, the equivalent addition would be only three more ist- 

 magnitude stars. The summation leaves off at a point where each additional magnitude is 

 adding more stars than the last. But, according to the formula, between the 23d and 24th 

 magnitudes there is a turning point, after which each new magnitude adds less than before. 

 The actual counts have been carried so near this turning point that there is no reasonable 

 doubt of its existence. Given its existence, the number of stars is probably finite, a conclusion 

 open to very little doubt. Van Rhijn estimates the total number of stars at 30,000,000,000. 

 Equivalent to 1440 stars of 1st visual magnitude in zenith, 1674 outside earth's atmosphere. 

 Density of radiation = 0.8 X io 13 erg/cm 3 . Millikan's cosmic radiation density = 4 X io -15 

 erg/cm 3 . 



Practically all the stars visible to the naked eye lie within 1000 parsecs of the sun, and 

 most of them are more than 100 parsecs distant. In the vicinity of the sun, the majority of 

 the stars lie within two or three hundred parsecs of the galactic plane; but along this plane 

 the star-filled region extends far beyond 1000 parsecs in all directions, and may reach 

 30,000 parsecs in the great southern star clouds (Shapley). 

 Smithsonian Tables 



