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INTERNATIONAL ASTRONOMICAL UNION Proc. N. A. S. 
to secure star positions, as far as possible, by photographic methods. This 
leads to the suggestion of the following meridian program, which is de- 
signed to provide the necessary foundation for photographic astrometry. 
The suggested plan, in brief, is to adopt 3000 fundamental stars as the 
initial basis of the system, to build about 40,000 reference stars upon this 
and then by photographic means to continue a list of reference stars to 
fainter magnitudes. The details of the plan follow. 
I. STANDARD STARS 
It is suggested that the list of fundamental stars compiled in 1910 by 
the Committee on Fundamental Stars of the Astrographic Chart, and pub- 
lished in the supplement to the Connaissance des Temps for 1914, be 
adopted. 
II. PHOTOGRAPHIC REl^ERENCK STARS 
As a secondary step toward providing a suitable structure upon which 
to base photographic plate determinations of stellar positions it is suggested 
that a list of stars be constructed, approximately one in each square de- 
gree, and included as far as possible between visual magnitudes 8.0 and 9.0. 
The list should favor the stars of the intermediary and reference lists of 
the Astrographic Chart, but in any event stars which have been previously 
observed should be selected. 
III. DIFFERENTIAL MERIDIAN OBSERVATIONS 
It is recommended that differential observations be undertaken in zones 
20° wide, four observations being taken of each star, two in each position 
of the clamp. All the fundamental stars in each zone should be observed, 
together with a sufficient number of fundamental stars at varying decli- 
nations to link the zone with the fundamental system. 
IV. REVISION OF STANDARD SYSTEMS 
Because of the rapidity with which the weight of a star position di- 
minishes, it is recommended that standard systems be revised every fifteen 
to twenty years, and that the results be incorporated in the ephemerides 
as they become available. 
V. QUESTIONNAIRE 
In order to disseminate information in compact form among the meridian 
observers, it is recommended that 6 months before each meeting of the 
International Astronomical Union the following questionnaire be sent to 
each observatory and that the reports be collated and published as part 
of the proceedings of the meeting. 
1. Brief' description of meridian work in hand, and estimated time of conclusion. 
2. Instruments, character, size, etc. 
3. Equipment: 
