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PR3TCHETT — EPHEMERIS OF SATELLITES OF MARS, iSSl. 357 



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r/ 1 



V 



ft 



P 



Date 



1881. 



Nov. 20.0 



26.0 

 Dec. 2.0 



8.0 



u.o 



20.0 

 26.0 



Jan. 1.0 



Brightness. 



1.00 

 1.07 

 1.15 

 1.21 

 1.24 

 1.26 

 1.24 

 1.18 



Semi-diam 

 Mars. 



Aberration 

 Time. 





6". 7 



7 .0 

 7 .3 

 7 .5 

 7 .6 



7 .7 

 7 .7 

 7 .6 



-5.7 

 5.5 

 5.3 

 5.2 



5.0 

 5.0 



5.0 

 5.1 



i 



From this it will be seen that Phobos, even on the most favor- 

 able date, will be only about 14" distant from the limb of the 

 planet. In 1877 this satellite was observed with the 12 J equa- 



M 



In the 



present opposition the satellite will be much fainter, but on the 

 other hand the brightness of the planet will be considerably di- 

 minished. It seems possible, therefore, that this satellite may be 

 seen with glasses of moderate size. 



Washington University, Nov., i8Si. 



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