A NEW DIGITAL DISPLAY SYSTEM FOR THE 1-METER TELESCOPE AT VAINU BAPPU OBSERVATORY

The Carl-Zeiss 1-meter telescope at Vainu Bappu Observatory uses synchro transmitters as angular transducers in a 3-stage geared train for the two axes coordinate display system. Synchro receivers are used in the console with analog dials displaying the position coordinates. In this approach the transmitters exhibit good performance and the receivers often suffer from dial sticking thereby resulting in ambiguous and inaccurate readings. The original Carl-Zeiss display system has a resolution of about 15 and 30 arc seconds in RA and DEC axes respectively. A new digital display system has been developed which replaces the synchro receivers with suitable electronics while retaining the synchro transmitters. This approach has resulted in better resolution (1.25 and 2.5 arc seconds for RA and DEC respectively) and accuracy over the analog display. This paper presents the hardware and software details of our implementation.