Table 89. 

 DURATION OF ASTRONOMICAL TWILICHT. 



(Interval between sunrise or sunset and the time when the true position of the sun's center is 18° 



below the horizon.) 



Date. 



Jan. i 

 ii 

 21 



Teb. i 

 ii 



21 



Mar. i 

 ii 



21 



Apr. i 

 ii 



21 



May i 

 ii 



21 



June i 



July i 

 ii 



21 



Aug. i 

 ii 



21 



Sept. i 



21 



Oct. i 

 ii 



21 



Dec. i 

 ii 



21 



NORTH LATITUDE. 



34° 



h. m, 

 29 



29 

 28 



42 c 



h. m. 

 1 4i 

 1 39 

 1 38 



1 36 

 1 34 

 1 33 



1 33 

 1 33 

 1 34 



1 36 



1 39 

 1 43 



1 54 



07 

 12 

 13 



2 12 



2 07 

 01 



54 

 4 S 



43 



30 



30 

 34 



33 

 33 

 33 



34 

 36 



38 



40 

 4i 

 4i 



440 



h. 

 1 45 

 1 43 

 1 4i 



1 39 



1 37 

 1 36 



1 36 

 1 3 6 



1 37 



1 40 



1 43 

 1 48 



1 54 



2 01 

 2 



46 c 



10 



2 18 

 2 23 

 2 25 



2 23 

 2 18 

 2 10 



2 02 



1 54 

 1 48 



1 43 

 1 39 

 1 37 



1 36 



1 36 

 1 36 



1 38 

 1 40 

 1 42 



1 44 



1 45 

 1 45 



h. 

 1 49 

 1 47 

 1 45 



1 43 

 1 41 

 1 40 



1 39 

 1 39 

 1 41 



1 44 



1 48 



1 54 



2 01 

 2 10 

 2 20 



2 31 

 2 40 

 2 44 



2 40 

 2 31 

 2 21 



2 IO 

 2 OI 



1 54 



1 48 

 1 44 

 1 4i 



1 39 

 1 39 

 1 40 



1 4i 

 1 43 

 1 46 



1 47 

 1 49 

 1 49 



48° 



h. m. 



1 53 

 1 52 

 1 49 



1 47 

 1 45 

 1 44 



1 43 

 1 43 



1 45 



1 49 



1 54 



2 01 



2 10 

 2 20 

 2 35 



2 54 



3 *i 



3 19 



3 10 



2 54 

 2 36 



2 20 

 2 10 

 2 01 



1 53 

 1 49 



1 45 



1 43 

 I 43 

 1 44 



1 46 

 1 47 

 1 49 



1 52 

 1 53 

 1 54 



50 



h. 



1 59 

 1 57 

 1 54 



1 52 

 1 49 

 1 48 



1 48 

 1 48 



1 50 



1 54 



2 00 

 2 08 



2 20 

 2 35 



2 58 



3 00 



2 35 

 2 20 

 2 09 



2 00 

 1 54 

 1 50 



1 48 

 1 48 

 1 48 



1 49 

 1 52 

 1 55 



1 57 

 1 59 

 1 59 



Smithsonian Tables. 



215 



