Abstract Details
| Name: SaiPrabhath Deevi Affiliation: IIA, Bengaluru Conference ID: ASI2019_481 Title : Development of a direct drive based Alt-Azimuth Telescope for the MASS-DIMM Intruments Authors and Co-Authors : Sai Prabhath D, Padmakar Parihar, Tarun Kumar Sharma and P M M Kemkar Abstract Type : Poster Abstract Category : Instrumentation and Techniques Abstract : The plane light wavefront from distant objects gets distorted while passing through Earth's turbulent atmosphere. The image formed by such wavefront is blurred and has scintillation (twinkling) effect. The MASS-DIMM instruments uses these two observable effects of atmosphere to understand its kinematic property. MASS measures the scintillation effect in stellar light and provides a vertical structure of atmospheric turbulence. DIMM uses the fluctuation in the phase of incoming wavefront and provides seeing. This helps in selecting a new site for astronomical observations as well as for effective implementation of adaptive optics. The efficient usage of MASS-DIMM instruments over a range of wind speeds require a very sturdy telescope, since the DIMM operation is highly impacted by wind speeds. To serve this requirement, a direct drive Alt-Az mount telescope was developed with in-house design at IIA, Bangalore. The cross-section area of telescope is minimized by usage of truss structure and anti-backlash is eliminated by direct drive which also helps in adjusting telescope stiffness dynamically. Three phase AC torque motors with stall torque capability of 39Nm are used for direct drive along with a high resolution optical-rotary encoder and interpolated in in azimuth and elevation axes. A slot type opto-schmitt sensor is used for telescope homing and proximity sensors for electronic limiting. Electro-magnetic brakes are being used for both axes when the scope is not operational. The telescope control system is implemented using controller from SideReal Technologies. The control application from Sidereal Technologies is integrated with in-house developed MASS & DIMM software. Functionality of the telescope is tested in the laboratory set-up, however, sky testing is yet to be done. The all sky pointing accuracy of the telescope is expected to be better than ten arc-sec and the tracking performance is expected to match with large size research grade telescope. |