The distiibution of the stars to the eleventh iiiagnittide 



43 



the decreasing intensities of the images. As the Hagen cliarts generally contain 

 fainter stars than the photographs, I accordingly arrive at a point, M'here the 

 comparison star has no corresponding initige on the ])late; then the limiting magni- 

 tude is passed. 



Regarding the probahle error in the determination, 1 have given it the value: 



0,1 when the series of comparison stars contains stars fainter tlian tlie limiting- 

 magnitude, and when the determination otherwise is good; 



0,2 when all the comparison stars are found on the plate, or when tlie images 

 are not well defined; 



0,3 when only a few comparison stars are given with great intervals in the 

 magnitudes. 



As one Hagen chart contains but a little part of the sky compared with the 

 plates of the Harvard Map, it is not easy to find the corresponding part of the 

 photogiaph. I therefore made use of the Bonner Burchmnsterunx) charts, orientating at 

 first Hagen's chart on these. In this way I always succeeded in the identification. 



More than one thousand comparisons have been made and the result is given 

 in table VI. In this table, the first columns give the numéro of the Hagen 

 charts and the name of the variables, the coordinates (a, 6), and the distance from 

 the centre of the plate (p). Tiie last three columns give the limiting magnitude 

 with the probable error, the number of comparisons and (he time of exposure. 



TAIîi:k vi. Tlie Limiting Mafpiitude. 



PI. 



Variable 



19 0 0 



P 



MagiiiUidc 





Ex. 







■ 1 



2 



188 Y Cephei 

 5601 B Ursae Minoris 

 7582 X Cephei 

 8629 Y Cassiopeiae 

 86U0 R — 



0"31"'16^ 

 15 33 27 

 21 3 35 

 23 58 14 

 23 53 20 



+ 79" 48,4 

 78 58,1 

 82 40,0 

 55 7,5 

 50 49,9 



6,1 



6,4 



4,3 

 1,0 



3,5 



11,4 + 0,1 



> 10,8 

 11,6 + 0,1 

 11,4 + 0,2 

 11,8 + 0,2 



12 



15 



28 

 5 



31»"' 

 63 



3 



8884 RR - 

 8324 V — 



65 X Andromedae 

 1279 U Camelopardalis 

 659 X Cassiopeiae 



23 50 47 

 23 7 23 



0 10 54 

 3 33 12 



1 46 42 



53 10,1 

 59 9,4 

 46 27,4 

 62 19,4 

 58 32,6 



2,2 



4,0 

 6,1 

 3,1 

 4,7 



11,4 + 0,1 



11 .8 + 0,1 

 11,4 + 0,1 



> 10,6 



10.9 ± 0,1 



17 

 19 



33 

 1 

 24 





4 

 5 



2376 S Lyncis 

 2186 X Aurigae 



3649 U Ursae Maioris 

 3460 W — 



G 35 56 

 6 4 25 

 5 53 39 

 10 8 14 

 9 33 32 



58 0,5 

 50 14,9 

 53 18,0 

 60 28,9 

 56 36,7 



3,0 

 6,0 

 4,1 

 5,2 



3,8 



10,7 + 0,1 

 10,4 + 0,1 

 10,6 + 0,2 

 10,6 + 0,2 

 10,9 ± 0,2 



14 



16 

 5 

 4 

 3 



59 



6 

 7 



4535 Y — 

 4557 S - 

 5948 R Ursae Minoris 

 5768 RR Herculis 

 5687 ST — 



12 33 42 

 12 39 34 

 16 31 20 

 16 1 28 

 15 47 47 



56 38,6 

 61 38,5 

 72 29,7 

 50 46,3 

 48 47,1 



3,9 

 3,8 

 7,8 

 7,8 

 8,4 



11,4 + 0,2 

 11,4 + 0,2 

 11,0 + 0,3 

 10,8 + 0,3 

 10,7 + 0,3 



5 

 5 

 3 



71 



58 



