Improved Precision Solar and Sidereal Clock

Abstract

An improved version of a Precision Solar and Sidereal Clock designed and built in the Raman Research Institute is described. For convenience in making corrections against standard transmitted time signals, the actual time displayed (solar) is I.S.T. Special features of this improved version are: It provides ‘Leap Second’ facility, by which seconds can be added or omitted from I.S.T. only without affecting the local sidereal time. The clock incorporates circuits which enable corrections of I.S.T. to coincide with standard time broadcasts, without the need for any external pulses. A 100 kHz signal is used for the divider chain which has improved the reliability of sidereal chain operation during power failures. In spite of using a lower frequency (100 kHz) for both I.S.T. and sidereal chains, the error accumulated in sidereal time is kept less than 40 ms/year ± the error in I.S.T. Many other changes incorporated in the hardware have improved the versatility of the clock.