Abstract Details
| Name: nilesh chouhan Affiliation: BARC, Mumbai Conference ID: ASI2019_293 Title : Mirror panel alignment procedure for the MACE Telescope Authors and Co-Authors : N Chouhan, V K Dhar, T Rinchen, S Norlha, Keshvanand, C P Kushwaha, A K Tickoo, R C Rannot, R Koul, N Gupta, M B Patil, V Sanadhya Abstract Type : Oral Abstract Category : Instrumentation and Techniques Abstract : The reflecting surface of 21m diameter MACE Telescope comprises a large area tessellated light collector, made up of 356 mirror panels of size ~984mm x 984 mm with each panel consisting of 4 diamond turned spherical mirrors of size ~488mm x 488 mm. The 4 mirror facets are assembled and pre-aligned in such a manner that the resulting reflecting surface behaves like a single spherical reflector. Each of the 356 mirror panels is supported on three ball joint pivots; two of these supports have linear actuators with a travel of ± 25mm which corresponds to an angular movement of about ± 2⁰ for the panel. The Active Mirror alignment Control System (AMCS) provides for small adjustments in the orientation of each mirror panel so that image formed by them is at the center of the imaging camera. AMCS is also required to correct for gravity induced deflection of the telescope basket at different zenith angles. The correction data for individual mirror panels as a function of zenith angle of the telescope will be stored in a look-up table prepared offline and the alignment corrections will be applied during observation using this look-up table. The telescope is at an advanced stage of installation at Hanle, Ladakh and 50 mirror panels have been installed on the telescope. The mirror panels have been aligned by pointing the telescope towards Polaris and adjusting their orientation. The D80 spot size of ≤ 26mm (~3.6 arc min) has been achieved with 50 mirror panels. Details of the procedure followed for the mirror panel alignment and the results obtained during MACE telescope assembly with 50 mirror panels will be presented in the paper. |