1G30 I^'igare of the Snii. 



]ata S^"'"'' °^ *^^ Planets (separately for each Planet). 



IbbU J^.g-ure of Satellites, incl. Ring- System of Saturn. 



ibbU h ig-ure of Comets and Meteoric Streams. 



IWO Perturbed Rotation ; Reaction on other Bodies. 



^ '^^ Precession and Nutation of the Earth. (See also 



02 GO, 3320). 

 1720 Movement of the Poles on the Surface of the 



Earth. 

 JI^^ Libration of the Moon. (See also 4830). 



:Lf: Libration of Planets and Satellites. 



1 i 50 Theory of Tides. (See also J 4 1 , 95). 



1//0 Constitution of the Solar System. 



^'*^^ General Laws of Distribution of Planets and 



Comets. 

 1790 Oi'igin, Stability, Development of the System. 



Stellar Universe. 

 1800 General. 



Jo Ja Structure of the Universe ; Stellar Systems. 



1 ^on Theory of Double Stars ; Calculation of Orbits. 



IhoO Resistnig- Medium, Ether,Temperature of the Universe, 



lb 10 Motion ol Solar System in Space. 



PRACTICAL ASTRONOMY. 



Observatories, Instruments and Methods of Observation. 



2000 Observatories (General). 



2010 History, Situation, Description, Reports, Per- 



sonnel, etc. 

 2020 Observatory Buildings. 



Domes, Piers, Rising Floors and Observing- 

 ^.^^ ^ Chairs, Portable Huts, etc. 



^030 Instruments (General). 



C)ld InstrumeuTs, Astrolabes, etc. 

 2040 Objectives: Glass and Manufacture of Glass, Com- 



parison of Reflectors and Refractors. (See also 

 C 3000-3100). 



Optical Matters, Images, Diaphragms, Screens 

 Visual Refractors. 

 Photog-raphic Refractors. 

 Photog-raphic Doublets. 

 Mirrors. 

 2050 Equatorial Mountings (Description etc.) and Driving 



Clocks. ^ 



Visual Refractors, Photographic Refractors. 

 Photographic Doublets (Portrait Lenses). 

 Mirrors. 

 Heliometer. 

 Heliostats, Coelostats. 

 Driving Clocks, Control Pendulums, etc. 



