8. Positional Astronomy

Extract

It is with deep regret that we mention the death, on 15 July 1969, of Prof. Dr G. Demetrescu who has done so much for the development of Astronomy in Roumania.

This report is based on letters received from members of the Commission, whom I wish to thank most cordially.

The most important events in the development of positional astronomy during the three past years were:

1. (1) The construction and use of new types of astronomical instruments based on new techniques, and

2. (2) The collective observations of large numbers of stars, especially in the Southern hemisphere on the basis of international cooperation.

At the USNO a design study for a ten-inch automatic meridian circle (ATC)was completed in 1968. Construction and installation should be completed by the end of 1970. A modified Cassegrainian optical system with a Cer-Vit primary mirror is being used. For some other important parts of the instrument new materials will also be used. At each end of the horizontal axis of the instrument Inductosyns will be mounted.

An Inductosyn system for digital readout of the pointing angle of the telescope was installed on the six-inch transit circle of the USNO in 1967 for testing and calibration. An IBM-1800 data acquisition and control system was on line with the same instrument.